One thing you don't do to anyone, is touch them without permission. A fan tried to reach out to touch Taylor Swift's leg during her performance of 'Bad Blood.' Needless to say, she was incredibly shocked. Watch the whole thing below:

It only lasted a few seconds, and you can see the guy being yanked away by fast-acting security guards.

Taylor, being Taylor, handled it like a pro.

Doesn't mean she likes it, though.

ope. Don't touch anyone if you don't have permission.