I was hiking in the smokies in the pouring rain...had my hood pulled tight to keep the rain out and my eyes on the ground to assure proper foot placement so I wouldn't trip over a rock or a root...all of the sudden WHACK...I hit my head so hard I literally saw stars and before I knew it I fell backwards into a mud puddle...there was a blowdown that was positioned perfectly so that I couldn't see it from the angle I was looking at the ground but was high enough that I hit it with my head...I was walking VERY FAST because I just wanted to get to the shelter where it would be dry and warm, so I hit that tree at full speed...it hurt really bad, but I found myself sitting in a mud puddle in the pouring rain and all I could do was laugh. I must have sat there in that puddle laughing for 10 minutes. That was the day I knew I was having fun out there on the trail.