 Just stress of every kind, right? There's people around all the time. It's hard to sleep. But I was lucky that I was on the first time I ever did it, that I was on a team that won because no matter who you are in that race, it's three weeks long. You're going to have days where you're just tired and want to quit. And it's a lot easier to motivate yourself to keep going when you're winning the race.