Daniel Jackson: Characteristics And Motivations
Peaceful Explorer
Daniel is a natural explorer, and his thirst for knowledge knows few boundaries. While he initially undertook the post at the SGC as a means to search for his kidnapped wife, the thrill of discovery kept him going during the ordeal and after her death.
Snake-Baiting
Because of what happened to Sha're, for many years Daniel's attitude toward the Goa'uld was one of pure hatred, and he sought any opportunity to destroy them, at times possibly unwisely (1.12 "Bloodlines"). However, he is also sympathetic to the beings who are their unwilling hosts. When the team captured Apophis and brought him back to the base as a prisoner, severely injured, Daniel visibly relished taunting the symbiote, but, when the host regained control of mind and body, Daniel was gentle and understanding with him (2.18 "The Serpent's Song").
His general indifference to his own personal safety and his sometimes unreasoning hatred for the Goa'uld have also caused him to engage, extremely recklessly, in 'snake-baiting' or mouthing off to the Goa'uld as well as physically seeking to thwart them. Such actions have earned him more than one back-hand (2.09 "Secrets", 3.13 "Devil You Know").
However, while he might hate the Goa'uld with an unreserved passion he has also demonstrated he is capable of putting aside his personal prejudices for the greater good of the mission and his other team mates. While he may be heedless of consequences to himself he does not knowingly endanger anyone else through thoughtless or reckless actions (Stargate the Movie, 2.17 "Serpent's Song", 3.3 "Fair Game", 3.06 "Point of View", 4.22 "Exodus", 5.15 "Summit Part 1", 5.16 "Last Stand Part 2").
Moreover, it is likely his first-hand experience of the absolutely corrupting influence of the Goa'uld racial memory given to him in a dream by Shifu (4.17 "Absolute Power") has caused him to question the wisdom of allowing his hatred to poison his soul. That he has considered modifying his position seems to be indicated by his response to Teal'c in which he said if Apophis were delivered into his power rather than succumbing to the desire for revenge, he hoped he would be able to chose the more rational option (4.22 "Exodus").
Making Friends And Influencing People
For the most part, Dr. Jackson is eager to make new friends among the aliens they discover. His gift for communication extends even to those cultures that have no concept of language (2.19 "One False Step"), as well as to those whose languages are not easily discernible (4.08 "The First Ones").
He is adept at turning enemies into friends, and in fact has succeeded in taming more than one 'savage beast' and making an extremely favourable and influential impression on many of the aliens the team has encountered (1.04 "Emancipation", 1.06 "The First Commandment", 1.10 "Thor's Hammer", 1.16 "Cor-Ai", 1.13 "Fire and Water", 1.17 "Enigma", 2.06 "Thor's Chariot", 2.07 "Message in a Bottle", 2.09 "Secrets", 2.13 "Spirits", 2.18 "Holiday", 2.19 "One False Step", 3.20 "Maternal Instinct", 4.05 "Divide and Conquer", 4.08 "The First Ones", 4.9 "Scorched Earth", 4.21 "Double Jeopardy", 7.07 "Enemy Mine", 7.10 "Birthright", 8.05 "Icon") not to mention two alternate versions of people he knows well in our reality but who had never met him (1.20 "There But For the Grace of God", 3.06 "Point of View"). He's also very good at recognizing when apparent friends are not what they seem (4.02 "The Other Side").
He takes his responsibilities as an explorer very seriously. When the arrival of SG-1 to the Rand Protectorate set off a religious uprising, Daniel insisted that Jack allow him to go back to the planet and try to head off a collapse of the government. While he did not succeed in stopping the rebel takeover or subsequent world war, he instilled hope in the survivors, helped them defeat the zealots, and promised the SGC's help in rebuilding their country (8.05 "Icon").
Moral Centre
His understanding of right and wrong have made him the moral center of his team, reminding them when the military solution is not always the key to the proper end, and finding alternatives to problems that seem to have no positive solution (4.09 "Scorched Earth"). In order to ensure the right course of action is followed and completely uncaring of personal consequences, he does not hesitate to question or defy any authority figure on world, off world, or at times members of his own team. Neither does he hesitate to throw himself into the breach, risking his life, and at times - giving it. He seems unconcerned with his own life when the lives of others hang in the balance, and willingly places himself in danger in order to search for answers to impossible questions.
His view of morality always drives his diplomatic efforts. His first step is always to see the other side's point of view and attempt to make them see Earth's. However, he refuses to renounce his morality either to save his life or to pacify a foe. Faced with the Doci and his Origin-based view of the single path to enlightenment, Daniel asserted his belief in free will and his willingness to die rather than give up that belief (9.03 "Origin Part 3").
Sometimes his belief in others' morality leads him to overestimate their capacity for doing the right thing. His desire to help Jarod Kane end his planet's civil war led him to be taken prisoner, and the subsequent effort to rescue him and stop the Ori's interference cost the SGC lives and a ship. In the end, the deal Daniel brokered did not hold, and the two warring nations destroyed themselves. Daniel's resigned disappointment was palpable (9.15 "Ethon").
Loss, Grief And Failure
Daniel tends to be very hard on himself — to remember his failures more than his successes. When faced with the chance to ascend, he admitted he felt his life had been a failure, and that his actions had led to Sha're's suffering and death. Only after Oma reminded him that his intentions had always been good was he able to believe he was worthy of ascension (5.21 "Meridian").
He appears embarrassed when receiving praise, as if he doesn't like to be the center of positive attention (7.04 "Orpheus", 7.07 "Enemy Mine"). At the same time, since his return from ascension, he seems to have come to terms with his life, to believe that finally he has found his place in the world (7.04 "Orpheus").
When it comes to grief and personal loss, Daniel often keeps his feelings to himself, though there is no question he feels losses deeply. In his dream of Sha're's death, he was reluctant to discuss his grief with his teammates and tried to keep from crying in front of them. Rather than turn to them for comfort, he decided to leave the SGC (3.10 "Forever In A Day").
After witnessing the death of his friend and doctor, Janet Fraiser, Daniel again sought no comfort, grieving quietly and alone in the room where she had tried to save him from radiation poisoning. Yet he turned his grief into concern for Janet's legacy, in the end insisting that the video of her death be made available to the documentarians. He overcame his own sorrow to help Airman Wells deal with his feelings of guilt over Janet's death, and he was there to help welcome Wells' daughter Janet into the world, again honoring Janet's life and what she meant to him. In all those events we never saw him seek comfort from anyone, though we hope it was given at some point (7.18 "Heroes Part 2").
Reverence For Life
Daniel was duplicated on P3X-989 (Altair), along with the rest of his team. Initially the doubles were forced to remain there, because the station where they were housed provided them with continuous power. If they left, their power supply would steadily diminish over a period of a few hours (1.18 "Tin Man"). However, the artificial Carter created a portable power supply which would allow them up to 48 hours away from Altair, and they subsequently began going out on "missions." The Jackson android was destroyed on Juna (P3X-729) by order of Cronus (4.21 "Double Jeopardy"). The rest of the Altair team was also destroyed.
This android encounter did not change Daniel's inherent respect for life in all its various forms. When SG-1 discovered the android Reese, he immediately related to her as if she were a human being. Her childlike innocence both charmed and alarmed him when he discovered that she was the creator of the Replicators, but he strove valiantly to create a sense of trust between them in order to get her to shut her "toys" down before they destroyed his planet. This consequently led to deeply painful angst between himself and Jack when the colonel shot Reese to prevent a take-over of the base and the planet by her Replicator bodyguards/army (5.19 "Menace").
Snarkiness
Daniel has always displayed his own brand of sarcasm, negativity, and snippiness, but it has become more pronounced since he returned from the Ascended plane. Perhaps as a result of increased maturity and confidence in himself, he is less patient when he feels let down by others, for example, when SG-11 mistreated some artifacts while mining naquadah (7.07 "Enemy Mine"). His encounter with manipulative alien Vala strained his patience beyond the breaking point; in the end he zatted her rather than listen to any more of her banter (8.12 "Prometheus Unbound"). After Vala arrived at the SGC, her constant manipulation and lying drove Daniel at times to distraction, so that even when she was sincerely trying to help, he told her to 'shut-the-hell up' (9.06 "Beachhead").
When frustrated, he has also been snarky with Bill Lee, referring to him as the 'bottom of the barrel' (9.04 "The Ties That Bind") and implying Bill had not yet done anything to warrant respect at the SGC (9.10 "The Fourth Horseman Part 1"). He's also aimed his snarkiness at Mitchell, yelling "New guy!" at him when Mitchell touched an alien device too hastily (9.09 "Prototype").
While he still tends to give others the benefit of the doubt on first contact, he is quicker to realize when he is being taken advantage of and to assert his own will. He is also less likely to waste his breath trying to change the mind of an opponent, quicker to recognize when such attempts are hopeless. For example, he knew from the start that Replicator Carter could not be turned from her objectives by anything he could say, so that his only option was to fight her (8.16 "Reckoning Part 1", 8.17 "Reckoning Part 2").
A 'Problem' With Heights
In Thor's Hall Of Might, undergoing a trial of bravery involving scaling a narrow beam across a bottomless abyss, Daniel confessed to having a 'problem' with heights (2.06 "Thor's Chariot"), but it is unclear whether he was joking or has an actual fear of heights. He seemed to have no problem scaling the over 22 feet high crate containing the Stargate in the DC warehouse in 1969 (S2-21,"1969"). He also maintained an eighth floor apartment in Colorado Springs and definitely did not seem to experience vertigo or otherwise react when he realised his was standing on the wrong side of the balcony's protective railing about to do something horrible before Jack arrived (4.18 "The Light").