Well, I wasn't there, but according to DH, it was the broken bike that caused the tears. He knew he wouldn't even be "just finishing."
The next year, he convinced me to take him for 2 of the 4 days of the race. The day of the crit, it was close to 100 degrees and the racers were fainting right and left. He pulled off the course and said, "Let's go, I'm done!"
Although he ended up being ranked #5 in the US, he actually never came in first in a race until right before he stopped racing. When he stopped obsessing over it, he won. But, he came in second or third a lot.
Make sure to keep it fun.