What's Your Favorite Text Message Abbreviation?

I may be a geek, but I can't stand when I'm chatting with people online, or via text message and they start using shorthands like BRB, TTYL and the always embarrassing TDTM.

I was completely against text abbreviations until a friend admitted she thought "LOL" meant "Lots of Love" not "Laugh Out Loud" and I realized everyone should at least know what the abbreviations mean, even if they don't want to use them.