I'm actually pretty well known for these. Just a few of my own sayings:
"Once I was weak, but now I am strong. I was foolish, but now am wise. You may have more money than me, more friends, and a bigger house and a cooler car. Despite that, I am still smarter than you and can rip your head off those pathetic excuses for shoulders. When it comes down to it, I'm still better in all they ways that count."
"Go ahead, live a fulfilling life. Get married and have 2.7 children and buy a house in the suburbs. Wait 20 years. You will have car payments, college tuition, a mortgage, stress from work, be fat, balding and arthritic. Brag about how great you are compared to me. I'll be retired on a beach in Maui not caring."
"Remember, only you can prevent forests"
"You will die eventually. Try not to make a mess."
"The glass in neither half full or empty. I just drank it. Really, what kind of idiot pours water just to look at it?"
"Never take a laxative and a sleeping pill at the same time. EVER!"
My personal favorite
"I don't care...wait...no, still don't care."