My biggest pet peeves:
1) PDA in front of friends. It's gross and no one wants to see that. If I wanted to feel uncomfortable I would go sleep in a bath tub full of bricks.
2) Couples saying I love you after a month or two. I did that when I was 18. Grow up. You barley know them.
3) Love at first sight. No explanation.

I'm so bitter sometimes.