My worst was years ago, after I had just moved to KY. Went to a local mtb trail, with which I was not familiar. Rode around for a while on the trails, then decided to pack up and head back to the house. That's when I got stupid. Exited on what appeared to be a path off of the trail. It was a deer path, that went to a slope with tall, slick, grass on it. Front wheel slid, I went down. When I looked around, my head (with helmet) was only a couple feet from a large rock. The bike at the time had a quill stem, and bars were pointing the same way as the top tube. I was fairly shaken up, even though I hadn't hit the rock. I recited (to myself), my phone number, address, birth date, just to be sure I wasn't concussed. STUPID mistake and went against all I've known forever!