I avoid restrooms when I'm with my granddad, just 'cause he gets annoyed when I use the men's. I don't care. XD
I stopped using the women's after this one day at a restaurant with my friend and his parents.
I figured they could see the bathrooms from our table, or his dad might come in, so I went to the women's. An employee was mopping the floors, and when I came in, she looked at me and said, "Excuse me, this is the..." and just stares at me for a really long time with neither of us saying anything. Then she just goes, "Uhm, the seats are wet." Cue nod. XD I love how confused she seemed.
It's so awkward for me to use the women's, even though I don't pass very well. I use the men's at school, even. I've seen guys in there who've heard people use "she" on me, or have even been told I'm trans, and they've never said a word to me. XD The principal was afraid I'd get raped, but stopped fighting it.
I mean, I even changed from my swimsuit to my regular clothes in a men's bathroom near this lake once. No stall doors, I used the shower and faced the wall. People walked IN. No one said a damn thing. XD
Edit: Remembered something.
First time I was ever IN the men's bathroom -- I was in 8th grade, post-haircut, pre-clothing being taken away. A guy friend and I were screwing around in the hall, he grabbed my backpack, I started chasing him. He went into the guys' bathroom, and I watched uneasily from the door.
Then I grew a pair, stormed in laughing, and went, "Boy, you think I ain't comin' after you?!" and he freaked out laughing that I was in the boys' bathroom. I snatched my backpack from him and walked out with it triumphantly over my head. A few people saw us and just figured we were stupid. XD