My worst diaper change was when I was at a car show last year. I had gone into a restroom at the back of this small western actor's museum in Wilcox Arizona, and thought that I had locked the door. I had my pants down, plastic pants down, and my messy cloth diaper laying on my plastic pants and the front of the toilet and was wiping myself clean when the door opens and this teen aged kid walks in and stops half way through the door. I just looked at him and said "excuse me", and he apologized and closed the door. I wasn't able to get to the door to check the lock, so I continued to clean up. After about 5 more minutes, another guys does the same thing. I was totally caught by surprise, and extremely embarrassed, to say the least.
After I finished, as I walked out of the restroom, the second guy that walked in on me was standing there waiting to get in. I just kind of looked right past him and didn't say a thing. Then I walked out to my car and put my diaper bag in it, and went to get something to eat at one of the venders there for the show. as I was walking over there, I saw the kid that had walked in on me, but he didn't seem to care, and never said anything to anyone around him when he saw me there, so I'm thinking he was just as embarrassed as I was.
That was my worst ever diaper change so far, but I know there will be more as time goes on, unless I become a hermit or something.