OK... a sci-fi hypothetical for you: Let's speculate that it becomes possible for you to send a message back in time, to yourself, 15 years into the past. You CANNOT send back any historic information (stock/metal prices, 9/11 events, sports or election results, etc.). You can ONLY send back general advice that is meant to guide your younger self without revealing future events and info you know about. You are limited to 100 words or less. What would you say?