I went clipless pretty quickly after I got back into a riding a couple summers ago... I think it was the second or third time I was out riding with the new pedals that I successfully rode the 11 mile loop of off-road trails that I used to live near in Tampa. Anyways, I was dead tired as I pulled up to the water station at the trailhead, and I made sure to unclip as I pulled my bike up to the bike rack. Unbeknownst to me, my right shoe inadvertently clipped back in, and so I of course lost my balance and fell forward onto the end of my handlebar as the bike laid down. The other handlebar hit the ground at the 'perfect' angle so that it didn't give/twist at all, thus my ribs took the full brunt of the impact. It totally knocked the wind out of me, and of course there were several people standing there getting water that saw it all happen. Worse, I ended up with some pretty nasty bruised ribs and was in some pretty severe pain for quite a while, it took nearly 2 months for me to fully recover.