There is a concept in books, plays etc. called "suspension of disbelief" The only really irritating characters are those who snap you out of the play or whatever into the real world, thus spoiling the play.

I recently watched (on BBC iPlayer) the version of Hamlet with Andrew Scott as the title character. He was amazing: you 100% believed him as the character, which such variety of stress, pauses and so on, that you had 'a real person' thinking and choosing just the right word to grasp at the right word, or with occasional slight pitch changes to indicate, mid sentence, Hamlet was unsure whether he had "quite got the right word there".

But his sheer skill showed up many of the others so you never really forgot they were actors. One actor in particular had a tattoo on the side of his neck which continually pulled you back to earth. (I find it odd that any actor would choose to have a visible tattoo - it must be role limiting.)