Day 02 — Your favourite episode

You cannot ask me this question! It's too hard. "Greatest Hits" and both parts of "Through the Looking Glass" would be high up on my list, especially because Charlie delivers one hell of a line in the latter (when Ben asks who had infiltrated the Looking Glass Charlie shouts, "It's Charlie, tell him I say hi!"). Anything from Season 5 is good too, I love everything about that season.