1. His great-grandfather was his great-grandmother’s second husband: walked into town one day, no friends, no relations, just the determination to make everything well for her and her children. An odd man, by turns overly-courteous and flat-out rude, but not afraid of work and so blindly in love with his wife that everyone forgave him his faults and his strangeness.
(Years after he’d died, she would tell her children’s children (and a few of their children) the story of a star who fell in love with a mortal woman and fell to earth because he couldn’t bear to spend eternity having never kissed her. But that story was forgotten by the time Jack was old enough to hear it; might have made certain events later in his life a little less unexpected if he had.)
2. He doesn’t have any siblings, but at last count his maternal first cousins weighed in at 32—and second cousins another 27. Not to mention all the once- and twice-removeds. Every year or two there’s a huge cousins party, although he stopped going to them after Charlie’s death, and was out of country for most of them before that. At odd moments of whimsy and despair, he considers the logistics/ethics of getting ATA gene tests done on the lot of them. His father's side of the family has a fair number of cousins, too (12 and 18 and innumerable kids), but he's never thought twice about testing them; there's a certain quality to his mother's family, something that sets them just a little bit off from the rest of the world.
(It's a quality he recognized in John Sheppard the moment they met, although he didn't realize that until the Atlantis expedition had been recovered and Sheppard was in the middle of yet another semi-hostile debriefing. Sheppard feels like family, although there's no logical reason why he should.)
3. Early mornings and late evenings, the moments between sleep and waking, when his house and bed and life ring empty, he thinks of Sara and what he had with her and what he lost. The rest of the time he’s too busy to notice.
He doesn't think of Charlie anymore.
(Except when he does.)
4. The thing with Sam is, well, the thing with Sam. They love each other, are sometimes in love with each other, but the program is more important--Earth is more important. What they have between the two of them exists only as far as it doesn't interfere with that.
(But it's all they have, sometimes, and there are mornings when Jack doesn't have cause to think of Sara and those are good mornings.)
5. Despite what everyone seems to think, Jack does not have John Sheppard all figured out. He’s got a better understanding of him than Landry does, and—judging from the paperwork—about 90% of Sheppard’s former commanding officers, but that’s all. A few aspects are familiar from Jack's mirror: the mask Sheppard wears (though his is one of indifference, not lack of intelligence), the burning need to do what is right and damn the consequences, the willingness to sacrifice himself for the sake of team and mission.
Sheppard thinks (at least Jack thinks he thinks) that Jack tests him to, well, test him. Really, though, Jack's testing his understanding of Sheppard. Because as long as Jack can control--appear to control--him, Sheppard remains a valuable asset to the program, despite his tendency to go off- (Landry's, the IOA's) book. So long as Jack gives orders Sheppard can obey, will obey, or can at least gracefully ignore, they're golden.
(Jack's respect for George Hammond grows and grows.)