13. And Don't Forget About His Blurred Sexual History
One of the main plot points throughout the early seasons of Friends concerns the fact that Ross has only ever slept with one woman, his first ex-wife Carol - and that's not something you're going to lie about, is it? What would be the point?
Cut to season 7, though, and it's revealed that Ross apparently slept with a cleaning lady whilst he was in college. Which means that... Ross is... purposely... making up the fact that... he only slept with... one woman? Why would you do that, Ross? Why?
12. Chandler Can't Cry? Not According To Phoebe....
The plot of episode "The One Where Chandler Can't Cry" concerns the fact that Chandler hasn't cried since he was a child and that he has no emotions, and that everyone now has to try and make him cry for the sum of the episode - and yet in series 3, a brief story is recounted about a time where Phoebe made Chandler "cry like a baby."
Which sort of ruins the latter plot, doesn't it? I mean, not really, but... sort of really. A lot.