Bruce Banner and the Hulk had a problematic relationship in the the weakest MCU movies.
Banner went through a recast for She-Hulk. Sadly, and even with all these appearances, the character of the Hulk wasn’t fully developed, leaving fans wanting more and questioning many moments and details about the character that were never explained, such as Hulk’s hate for Banner in Avengers: Age of Ultron.
As mentioned above, these two have a very complicated relationship, with Banner trying to get rid of the Hulk many, many times, even trying to kill himself only to have the Hulk showing up to spit the bullet. The conflict between them was more evident in Avengers: Age of Ultron, specifically in the scene where Banner lets the Hulk come out after Scarlet Witch played with his mind, causing him to escape and create chaos in the streets of Johannesburg. Tony Stark then used the Hulkbuster to try to calm him down and bring Banner back, but as soon as the Hulk heard the name “Banner”, he reacted aggressively, with Tony reminding himself to not mention “puny Banner”.
Age of Ultron doesn’t explain why the Hulk is so angry with Banner, instead focusing more on his relationship with Black Widow, but the comics offer an answer to the question. The Hulk hates Banner because he sees him as a pushover, and it’s actually a very understandable conflict as they are opposite personalities inhabiting one body: Bruce Banner is driven by reason and science, while the Hulk is all about emotions and his very bad temper, even showing a childlike personality in other versions (as happened in Thor: Ragnarok). In addition to that, Banner has worked hard to find a way to either get rid of the Hulk or at least lock him to have more control over him, so with that in mind, it’s understandable that the Hulk doesn’t like him.
Hulk getting angrier when hearing “Banner” in Smart Hulk” and putting an end to their rivalry, but in a way, that also gave the audience the freedom to interpret the Banner/Hulk conflict in different ways.
