12. The Sixth Doctor (Colin Baker)
With quite possibly the worst fashion sense in the entire history of the show, Colin Baker's Sixth Doctor looks like a bad cosplay of himself.
With such a bright and colourful costume, you might think that this Doctor would be incredibly easy to like, but Baker's incarnation was surprisingly arrogant and self-absorbed, to the point of being off-putting. The poor reception to his era resulted in him being let go by the BBC - the only Doctor Who star to suffer such a fate - and he didn't even get to film his own regeneration.
The fact that he was fired hasn't helped the negative perception of his tenure in the years since, and perhaps if he had segued out of the role naturally, it would be possible to look back on Baker's time in the TARDIS with a bit more fondness. But despite some terrific audio stories courtesy of Big Finish (The Curse Of Davros being a particular standout), the Sixth Doctor's TV portrayal is still hard to get onboard with.
That being said, we will give Baker and his creative team some credit: this was a bold direction to take the character in, even if it didn't really work out.