Matthew Vaughn directed X-Men: First Class, which was pretty successful for an X-Men reboot. Vaughn was also set to direct its sequel, titled X-Men: Days of Future Past. But recently, he inexplicably dropped out of the project, and the rumors started to fly. But it appears the real reason he left X-Men was to work on The Secret Service, an upcoming spy thriller based on the comic he co-created with Mark Millar and Dave Gibbons. So why couldn’t he have worked on both?