I was having this conversation with my dad on the way home from my xc last race. He was saying that my mom would like to see me just out on the bike having a good time and didn't even particularly want me to race. I told him that I race because that's what I have the most fun doing. It makes all of those rides that have fireroad climbs that seem unending feel more worthwhile. It also gives me good goals to work for. I can see that the training rides are paying off when I am able to pass people that were beating me by 2-3 minutes last year. It gives me that sense of accomplishment that I can't get with just riding. Sure regular riding is great and you are able to make accomplishments like clearing crazy rock gardens but it doesn't feel as rewarding as being able to compete and overcome things in races.
Those are some of the major reasons that I love to race. There are more and I'll post them if I think of them but I was wondering why others race as well. Any type: XC, DH, 4x or whatever. Give us your reasons.