Well, this one was surprising, wasn't he? Nobody - not even the man himself - could've predicted that Mickey Smith would turn out to be such a formidable force to be reckoned with when he was introduced as Rose Tyler's bumbling boyfriend back in Series 1. After being abandoned by his long suffering girlfriend without a second thought when she opted to travel the universe with a mysterious stranger instead, it was more a case of Mickey missing a pair of balls than the fans actually missing him. To the frustration of every single person watching at home, he remained at Rose's constant beck and call whilst she went galavanting through time and space (hell, he was even accused of murdering her when she disappeared for a year!) and it wasn't until Series 2 that he finally decided enough was enough and embarked on a mission of self discovery to establish himself as a bonafide hero in his own right. Sarah Jane once chortled that there should always be a Smith aboard the TARDIS and, while Mickey never quite made the cut, he definitely deserves credit for his transform from would be tin dog to fully fledged Earth defender. Not too shabby for a character who was originally only in written in for 3 episodes. It worked out pretty well for Martha Jones, too, but let's not get ahead of ourselves...
Dan Butler is the Doctor Who Editor at WhatCulture.com. When he isn't writing his own articles or editing other people's, he can be found trawling the internet for gifs of Steven Moffat laughing. Contact him via dan.butler@whatculture.co.uk.