We can appreciate how that would begin to wear down one’s nerves after a while.
Still, he does say that the shooting of his final season took 10 months, so, while the show may only make 12 episodes, it apparently takes much longer to do that for Doctor Who than an American network series would take to film twice as many.
The bit about not hating the job was sort of fed to him by the host of The Graham Norton Show, where Peter Capaldi made the comments, so we shouldn’t read too much into the idea that Capaldi hates the role, or was on the verge of doing so.