I confess that certain things tick me off about movie scripts.
Ok, people do say "hey" when they meet today. However, when you have a movie that is supposed to have taken place in the 60's, 70's, and people say "hey" when they meet, it sounds strange. The cars are right, the clothes are right, the hair is right. The "hey" isn't. Just watch any movies from the 70's, and you will not see (or hear) anybody saying "hey".
Then there is the "um".
I don't know if there is any new acting school that says that good acting is saying "um" every three words. Certain actors and actresses abuse the "um" so much, that it sounds as if their parts are written with 1500 "ums" intercalated with a few real words.