1. Yes, guys with long fingernails
While I don't remember ever being scratched by anyone, I too did notice that a lot of dudes in Japan don't seem to trim their nails very often for some reason. Maybe they just don't care? It was kind of off-putting. One time when my mother and sister visited and came to my base school to meet some of my coworkers, my sister pointed out later that the principal had a really long pinky fingernail.
2. Girls who shave their arms
This is something I like about Japanese women. A lot of them shave their arms. I don't mean this to disparage any women who don't, but I personally find it attractive. I mean, a lot of women shave their legs in the West. This just seems to me like a natural extension of that practice.
3. Fake pigeon toe or bowleggedness
At least I think it's fake. It's been pointed out before, but a decent amount of Japanese girls tend to stand with their knees and feet facing inward towards each other, presumably because this is cute. I'm not exactly sure why this is considered cute, but I think it looks a bit dumb.
On a related note, I've actually been noticing the opposite here in the States. Recently I have been spotting people who point their feet outwards when walking (especially noticeable when wearing flip-flops, I think).
4. Old women with blue or purple hair
What's up with that?