The Marvel Cinematic Universe has explored the darker sides of its heroes in tasteful and creative ways. One of the best examples of this was Tony Stark's bout with alcoholism. While this topic couldn't be explored in the movies, it was explored starting in Iron Man 2 through his fear of death via Palladium poisoning. The fear led him to make mistakes until he picked himself up, and that same fear returned with Thanos as Tony's anxiety had him create Ultron and lose half of life in the universe. But Tony wasn't the only hero whose vices were explored.
Source：https://www.cbr.com/captain-marvel-workaholic-status-biggest-weakness/
