Jack draws people to him like a magnet, and he does so effortlessly. His smile is wide and white, completely unforced, oozing charm and charisma, and people of all kinds simply gravitate towards him. The only people so far who haven’t fallen under his spell are the Daleks, and the Doctor himself. Even Rose isn’t immune.
The Doctor isn’t jealous, or envious, or resentful, merely puzzled, because he can’t for the life of him understand why Jack has such a profound effect on almost everyone he meets.
“Face it, Doc, I’m just that irresistible. Everybody loves me!”