Good question gikitiki. I think it would depend on the age. At 4 years old I would have told myself to use a tissue. At 8 years old I would have told myself not to annoy Darren Jones too much or he'll stab you in the hand with a pencil. At 22 years old I would told myself to save up for a home and stay away from the $30k in credit cards that were offered to me by the banks.