I don't care what you think... STFU (shut the fuck up)
Don't add me if you're not going to comment me.kthnxbye. (kay thanks bye)
don't talk to me in flippy caps (LyK DyS)
I'm good, hbu (how bout you)
I heart you, I <3 you (casual way of saying "I love you")
note: multiple 3's can be used for added effect (<3333) or <321, <3456789, <1+2, etc.
Your hair is the sex (very cool)
tha'ts uber cool. (very)