...I mean like real people, ya know?
It's not exactly a pet peeve with me, but it sure does discourage me from reading what might otherwise be a good story if the characters don't talk like real people do.
It's why we invented contractions like "it's", ya know?
And another thing. The way a character talks can be used to establish the character, identify him or her, distinguish them.
For example, a selection from my own writing:
"Hi! I'm Judy Liu. You're new here! Are you okay? Can I help?"
"I am Hadiya," she responded, amazingly calm, bobbing her head without really looking up. A colorful scarf concealed her hair, hung over her face."I do seem to have offended someone."
"That was Dolph Foster. He's just offensive, 'specially to anyone who's not his color. We try to avoid him, but that's not always possible."
"He is what you would call a bigot?" She had a lovely accent.
"He is what we call an asshole."
See what I mean? English is a second language to Hadiya, so she's more precise. Judy Liu is American to the core and sounds like it.
LISTEN to your characters. Hear them in your head. Don't make them all sound like they're reading from a dictionary.
Ya know? I mean, see what I mean?
'nuff said?