The actual tower took weeks to build and remodel, what with all the city cleanup that had to be done. Tony Stark had extended his invitation for the newly formed Avengers to make it their new base of operations, assuring each of them that "you'll get your own floor, all to yourself, so you wont even have to see me if you don't want to, except for movie night." In the meantime their demi-god returned to home and the SHIELD agents, who'd reluctantly agreed to join the initiative, stayed on the helicarrier, while Steve continued to sleep at the SHIELD-rented apartment.
Bruce, somehow, had been convinced to stay in a guest room at Tony's New York house - his second New York house, since the primary one was off-limits during remodeling. Bruce wasn't entirely sure how he'd been talking into staying at all; he enjoyed the camaraderie, but a subtle disappearance sounded like a good idea to him.
"Nonsense," Tony said when Bruce quietly mentioned that he probably wouldn't be staying in the country for very long. "Of course you're staying. You haven't even seen my labs yet." Without much thought, Bruce agreed that, yes, he did have to stay at least long enough to properly tour Stark's personal labs. As a reward, Tony nudged the bowl of almonds half an inch and invited Bruce to take some as they continued their work.
Bruce tried not to comment on how much he liked almonds, or on how obvious Tony's tactic was. He wasn't sure whether to be honored or insulted that the billionaire scientist was trying to use Behavioral Conditioning to force a friendship. But the thing about Positive Reinforcement is that it works even if you know it's being used on you.
Tony showed each of the Avengers around their new home after the tower was finished, obviously very proud of his work even if no one allowed themselves to act very impressed. When he was complimented on the design for Bruce's personal floor of the building, Tony smiled and handed Bruce the bag of pretzels he'd been working on for the past hour, before leaving to go deal with the recently returned Asgardian. Bruce noticed that the bag was marked 'organic'.
Pepper Potts found Bruce after Tony left. "I just wanted to say thank you," she said, handing him an identification card with his name on it.
"Tony's never been a horrible eater," she explained, "but he's been paying more attention to what he eats since you showed up. He says he doesn't want to be left without something to share."
Bruce nodded knowingly. He and Pepper had become friends during the past weeks - though she would say that was to be expected, that it would be hard for anyone not to befriend with Bruce, and he would say the same of her - and they both knew what was really going on here.
A month later Bruce realized that he had ended up staying on at Avengers Tower indefinitely with the others, lending his knowledge to Tony's projects and the 'other guy' to the team when more baddies showed up, as they often did. Despite their rough start, the team was actually getting along pretty well now.
It turned out to be a near-perfect arrangement, despite the 'other guy's previous tendency to want to separate. Bruce thought idly to himself, from time to time, that in another universe the Hulk would have abandoned the team and been long gone by now, unable to stand the group atmosphere. Instead, he was still here, risking his and Bruce's lives to protect the team, and catch Iron Man whenever he fell from the sky.
Bruce almost wanted to thank Tony for that, but decided against it. It seemed odd to thank someone for the cheap tricks they used to make you an asset, even if the situation was ultimately beneficial to both of them. Instead he accepted the chocolate when it was offered - dark, as he had casually mentioned to Pepper - and worked on making Tony's lab feel, as it should be, a little bit more like home.