The other day at McDonald's, because men's toilet was full, I used the disabled toilet, which doesn't get used often and hence is clean most of the time. Then only a few minutes (really only two or three minutes) after I got in there, someone tried to open the locked door, but obviously it wouldn't open because it's occupied and locked. Then that woman started to talk "oh, it's locked, are you ok in there?" I ignored it because I found it intrusive of her to talk to someone in the toilet. She kept asking "are you ok? blah, blah, blah..." It wasn't as if I were in there for even 10 minutes, which would still be normal. It made me very uncomfortable and angry. There was absolutely no reason to suspect anything unusual was happening there. In the end I snapped and told her she was being very intrusive and rude. She then shut up and left me alone. I wonder if she actually did it to harass me because she didn't like it when she found the toilet being used when she wanted to use it.
I find it very intrusive when anyone (except my family at home asking me if I want coffee with them or not, or anything like that) talks to me when I'm in the toilet, because it's a very private moment. Such things make it very uncomfortable for me to use public toilets.