A bad habit
I used to bite my nails. My nails looked poor and ugly because I was biting them anytimes. Sometimes it was bleeding but that didn’t make me stop doing it. I always had short nails. My mother worried about that because of hygiene and didn’t want to see my bad habit. After grown up, I stopped biting. However when I feel nervous, I tear my nails off shortly. I’ve had a new bad habit again.