Just a Random Question

I was hit by a strange question last night (I say "hit" because once I thought of it I could not stop thinking about it). The question is this: If you could go back in time to your senior year of college (or that age equivalent) and tell your past self one thing, what would you say? Would you warn yourself about mistakes and bad habits? Would you encourage yourself to do something different, like asking that cute girl (for me) on a date? Would you pass out in shock after seeing your past self and realizing how much hair you had, how thin you were, and how much optimism you had about the future?

Just a random question on a random eve.