8 Actors Who Regretted Leaving Doctor Who
6. Matt Smith
Matt Smith's Eleventh Doctor spent the second half of his final series travelling the universe with companion Clara Oswald, played by Jenna Coleman.
It was a typically friendly Doctor-companion dynamic, albeit one with a lot of tension bubbling beneath the surface, mainly on the Doctor's part. He couldn't fully trust her because he didn't really know who she was, a mystery that wasn't resolved until series finale The Name Of The Doctor, which revealed Clara's "Impossible Girl" backstory.
The Eleventh Doctor regenerated a couple of episodes later, which, from Smith's point of view, was a bit of a shame, because he wishes he'd got to spend more time with Coleman by doing an extra series of the show.
At New York Comic-Con in 2016, Smith stated that one of his "great regrets" is that he left Doctor Who without getting to do a full series with Coleman (remember, they only got to do half a series together, at the back end of Series 7).
Eleven and Clara were a fun pair, and it would've been nice to see them get a complete series set after the conclusion of the Impossible Girl arc. Big Finish, help us!