What do Marvel actors really think of their roles?

Since 2008’s ‘Iron Man’, the ‘Marvel Cinematic Universe’ (‘MCU’) has become a cinema staple that continues to add more and more Hollywood A-listers to its seemingly-never-ending roster.
Whilst, plenty of actors have emphasised playing their parts had been a career highlight, several have also admitted they were happy to step away from their characters and the franchise.
So, what do these Marvel actors really think of their roles?