Let's see....There was one time at school when I was caught off-guard to answer a question. That day was also my birthday. What was worse was that the single best answer to the question was "Birthday." My teacher even forgot about it too. So I tried to think of another answer, but I spat out "Uhhh... Birthdays?" Almost the whole class just stared at me. My teacher just laughed.
That wasn't a very good way to end class, either...
I don't remember a most embarrassing thing, but AN embarrassing thing...although nobody saw.
Unfortunately, some of the pairs of pants I have do tend to slip down when I'm walking, even when tied up. And although I don't wear them often, there have been times where I've had to hold my pants up in the middle of, say, carrying in firewood from outside.
Now I dunno about you, but that's embarrassing to me to think if anybody saw that. ><