7. Avi Arad
Of all the people Marvel probably regret upsetting, you have to believe that Spider-Man producer Avi Arad is very low on their list. When a Businessweek article and interview with Kevin Feige gave him full credit for the creation of Marvel Studios, Arad was quick to tell anyone and everyone who would listen that he was responsible for Marvel's slate. Clearly still upset with Feige not giving him the credit he believed he deserved, Arad would spend the entire press tour for The Amazing Spider-Man 2 making it clear that Sony would not come to a deal with Marvel which would allow Spidey to join The Avengers. Unfortunately for Arad, when the sequel bombed, his bosses decided it was Feige who they needed to save Spider-Man, and the Marvel boss had Arad dumped from the franchise. In fact, it was one of Feige's specifications that Arad not be involved in any way, shape, or form with the reboot, proving that there's actually a lot of bad blood on both sides.