In 20 years of track driving, I lost control a few times. Most often it was because I got tired and/or over ambitious. It doens't take much:
Sometimes, it's not me. That day, Fast Toys rented me their expensive car with totally trashed tires. I kept telling them, they didn't really listen until the tires were visibly corded, and then put another set that was also mostly trash :(
This one was my fault, went a tiny bit wide, the underneath of the very low car, caught, spun me, and caused 10K of damage :(
And then, there is snow, I have many more, but just one: