Back when I was in 9th/10th grade, I was a member of a club at the neighborhood library that met twice a month. The high school I attended at the time required a (quite frankly hideous) uniform, and on days when I had a club meeting, I didn't have enough time after school to get off at my bus stop, go home, get changed into street clothes, and then go to the library, so I'd just go to the meetings in my uniform. In 10th grade, after I'd been a member of the club for over year, I had my first day when a "casual dress" day at school overlapped with a club day, since that day was our in-school performance of the Christmas concert. So when I went to my club meeting, I was wearing a normal outfit - nothing special, just a sweater and some nice jeans, but it was something I would usually wear for a walk, unlike the uniform. I walked into the club room, and when one of the boys looked at me, the first words out of his mouth -
"Wow, Irk! I've never seen you wearing clothes before!"
It took a bit to make the room of 15-year-olds stop laughing.