Funny thread...
Most embarrassing:
Trying to take my arm warmers off while riding (no hands) - I started to loose control of the bike and swerved into gravel at the side of the road. Yard sale!
Scraped elbow – check
Torn knee warmer – check
Scrapped leg - check
Bruised ego - check
Truly most humbling:
I trained on a 2-mile, 8% grade hill for months. During one climb I was nearing the top and was about to achieve a personal best time when I got passed like I was standing still by another cyclist.