**This may come off as a rant, but it's really meant to be more contemplative**
Overuse exclamation points (i.e. !!!!!!!) for very small things. If you're going to pretend to be all excited about something insignificant, what will you do when something really monumental happens?
Tell me how smart you are, or ask me how smart I am. Especially if this involves some sort of quantitative number, like a GRE score. Seriously, are we in grade school? That is none of your business and you should know that the number is a reflection of nothing. Some of the smartest people I know do not do so well on standardized tests.
Not look at my face when I am having a conversation with you. I'm particularly disturbed when you always seem to be looking behind or around me, as if you are waiting for someone or something more important to come along.
Talk about your pets as though they are your children.
Be one of those girls that is always "not that hungry." Food is good, you should eat it.
Be really, really into video games in addition to being in your twenties (or thirties).