And sometimes they can be pretentious know-it-alls! As I stopped to pay my repair bill after the completion of repairs from my Big Crash, a smug skinny guy proceeded to lecture me on bike technique, even inviting me to his clinic! He smoothly informed me I was doing things wrong and came about a breath away from implying that I crashed due to sheer stupidity. Naturally, he would have been carried over that set of train tracks on the backs of angels singing hymns to his goodness.
Here's the real lesson for us. Did I use the best technique for going ovr the tracks? Of course not... I didn't see them in time to properly react. It's called "going too fast for the conditions", not "bad brake technique". When one's front tire is skidding out, you should not apply the front brake, but rather, try to float until you are on firm ground again.
you should also realize that everyone can crash, and everyone does at one time or another. Riding can be dangerous, and no one is so perfect that they avoid crashes.
Not even you, Mr. "I've spent hundreds of hours training to become certified". Let's just say you ticked me off!