I read this before every big race. You should too. I get goosies every time.
"The purpose of the swim is to get you on the bike. The purpose of the bike is to eat for the run. The purpose of the first run lap is to put money in the bank to pay the monkey that will jump on your back the second lap.
The Second Lap Monkey. He is a very big monkey. If this is your first Ironman, you have probably felt in your training everything you will feel on race day, except the Second Lap Monkey. You can't train for that. The Second Lap Monkey carries a big stick, and its name is Pain. Love it, hate it, get angry at it. Breathe it with every breath, feel it every step and use it.
It lets you know you are still alive, more alive than most people will ever be in there lives. The clock keeps on ticking and everything bad must eventually come to an end. All you have to do is keep running in a straight line until someone tells you to stop."