Meaning/Usage: Used when someone makes a mistake that they shouldn't have made

Explanation: This is used more commonly with children, but can also be used to adults. However, this can make the person feel a little bad because you are speaking to them like a child.

"Mary said you were rude to her, you know better than that."
"You know better than that. Now pick up the mess you made before going outside."
"Come on, you know better than that."

A. "Did you yell at your sister for playing with your toys?"
B. "Yes, she didn't ask me."
A. "Well you know better than that. Next time use your manners and ask her nicely."
B. "Ok mom, I'm sorry."

Other Common Sentences

"You know the right thing to do."
"You know what you were supposed to do."