When you are backing out of a drive and you knock your muffler on the ground. I was leaving my friends and it was the first time I had been to their new place. The drive is pretty sloped and has a dip at the bottom. I thought I would be ok. NO! I hit my muffler and when I put it in drive I heard it dragging. CRAP! I had knocked it off the hanger. No big deal right? Only one problem I lost the rubber piece that hangs the muffler to the piece on the frame. Finally I found it (luckily I had a flashlight). But, I had to ride home wet because I had to lay on the ground and it had started to rain. What a night!