Why is it bad manners to stick your chopsticks in your rice?

I have a bad habit of doing this while I'm eating that I'm trying to break lol

PS. is it also bad to put them in other foods?
Update: Thanks everyone, I learned to use chopsticks from my filipino friends when I was 6 or 7 and have been using them that way for years. I want to go to Japan someday so I'm changing my habits, I won't do this anymore :) PS. since I posted this in the "Japan" section I didn't feel the need to... show more Thanks everyone, I learned to use chopsticks from my filipino friends when I was 6 or 7 and have been using them that way for years. I want to go to Japan someday so I'm changing my habits, I won't do this anymore :)

PS. since I posted this in the "Japan" section I didn't feel the need to specify that I was talking about a Japanese custom.
15 answers 15