Seinfeld

When Kramer asks, Morty explains how he came up with the idea for "The Executive". He claims to have tripped over one of Jerry's toys, removed the belt to threaten Jerry with, and seen himself in the mirror. According to his story, the next day, he cut the beltloops off the trenchcoat. However, in Season 2's "The Pony Remark," Morty says that he came up with the idea for the beltless trenchcoat when he went to work for "Harry Flemming" - as if it were a normal part of his job, and not an accidental innovation. Furthermore, in that episode he says that he came up with the idea in 1946. This episode aired in 1991, at which time Jerry was certainly not in his 40's. As such, it would be impossible for Morty to have tripped over Jerry's toy in 1946. It is therefore impossible for both explanations to be true.