Something you find attractive that isn't usually thought to be?

I got a tattoo last week on my back so it couldn't be seen in day-to-day activities. It's all black, and I just realized you can see it through my shirt if I'm wearing white. It kind of annoys me since the idea was to keep it hidden. I told some of my female friends this (who also have tattoos) and they think it's really hot. I had no idea.

Are there other, subtle things that are attractive that you wouldn't normally think about?