When did Doctor McCoy (Star Trek) turn so sarcastic?

In the show he doesn't seem sarcastic or mean at all, but when
watching Star Trek: The Motion Picture, he seems to be very sarcastic
and seems not to like Spock very much. Even when he gets beamed up at
the beginning of the movie, he seems weird and is saying weird things
lol.

Did this happen on the show or was this only done for the movies (or
the first movie)?