7. Friends - Season 4 Finale (The One With Rosss Wedding, Part 2)
One of the funniest and most gasp-worthy moments in the show's history, the cliffhanger to Friends season four saw Rachel watch Ross at the altar with Emily, realising too late she had lost her chance with him, despite flying all the way from New York to London to be there. Fans were wondering just how this situation would resolve itself - particularly if Ross and Rachel were destined to end up together - but no one could have expected those immortal words "I take thee Rachel". When the episode was first broadcast, it left viewers stunned. Now re-watching the build up to that moment you can't help but cringe at what is coming. So simply done yet taking the Ross/Rachel love story to the next, unexpected level, season four left the show on a hilarious cliffhanger that had people wondering just how Ross was going to get out of this situation.