My brother just asked me if I've ever wanted to do anything in life but just kept putting it off. It's a tough question and my first reaction was to gape at him but I did have some answers in the end.
1. Learn how to play the guitar
2. Travel ("Where?" "China... And Turkey.")
Uni exchange trips are great too!
3. Volunteer (regular CIP plus OCIP)
4. Be more immersed in the arts and social sciences (I guess this will be during uni)
Now that I'm at it, I have one more!
5. Exercise more (play badminton, go for Hip Hop, etc.)

The grass on the other side is always greener. My mum and brother seem very envious of the lifestyle I have now, which is slacking every day.