Science Bros Headcanon #83 Tony can be jealous of anyone who makes Bruce laugh, especially if they get him to laugh really hard. Tony used to be so proud of the fact that he was the only person who could make Bruce laugh until he cried. Once Bruce got more comfortable with the team, it was no longer his special thing with Bruce. Though, he does enjoy the fact that Bruce is no longer as reserved and tense as he used to be.
Science Bros Headcanon #108 Bruce has a huge sweet tooth, but he tries not to indulge it because he associates sweets with impulse and loss of control. So, naturally, Tony has taken to leaving all sorts of desserts about the lab, in hopes of getting Bruce to eat them.
Bland Marvel Headcanon - the one where Loki befriends the author of the older Edda, who takes his silly, joking tall tales of home as truth and writes them down for posterity (Thor having to dress up as Freya, Loki having a baby with/as a horse, etc)
Science Bros Headcanon #126 Tony loves it when Bruce gestures with his glasses so much, that he has developed the habit of asking Bruce knew where things are, just to see him point to the item in question with his glasses. Tony knows where all of these things are, since it’s his tower after all.
Science Bros Headcanon #144 When theyre at home and Tony wants to get Bruces attention, he will often times resort to calling Bruce Robby-Pooh" in a sickeningly sweet voice. Tony is the only person allowed to call Bruce by any variation of his given first name, Robert.