8. How I Met Your Mother (2005-2014)
What Was So Bad? It's hard to believe that one of the funniest and most innovative shows on TV started out life as a Friends rip-off, but if you watch the pilot of How I Met Your Mother, that should be far from a shocking revelation. Even though we meet our characters several years into their romantic relationships and bromances, there's little chemistry between the actors and thus the characters, and it really shows on screen. There's some good gags scattered throughout the episode, but it's excruciating at times with the awkwardness and cynicism going on.
How Did They Fix It? Neil Patrick Harris' Barney Stinson was recognised as the standout character of the show and was used a lot more in subsequent episodes, meaning we got to find out more about the character as time went on, instead of him just being the creepy single guy who hangs around with two couples. The other actors also seem to fit more into their roles and better chemistry is the consequence, making it a much better show. More 'fantasy' and cutaway scenes were introduced, and the premise itself was simplified and the narration reduced, with the show now feeling less like an extended flashback and more like a current TV show.