One day a few years ago, after finishing a twenty-mile run at the gym, I stepped into the shower to rinse off, and went out to the pool to do a few relaxing laps. There was no one out there except a young woman swimming in the closest lane, headed up the lane toward me.
I walked about twelve feet from the door to where there are some hooks on the wall to hang my towell, looked down and saw that I was holding my bathing suit in my hand.
It took about two frantic microseconds for me to charge back into the locker room. Fortunately, no one else was around, and I'm pretty sure even the lady swimming probably didn't notice, but I don't know that for a fact.
I could have put my suit on and gone back out, but I was too embarrassed, not only for myself, but for the possibility that if the girl had actually seen me, it might have paniced her into thinking some perverted nut case was on the loose, particularly with no one else in the pool area. So I just got dressed and left. I was otherwise done working out for the day.
Honest mistakes are sometimes very hard to explain. But how much attentiveness does it take to remember to put your pants on before stepping out in public?