What means to drive around the bend?

The phrase "to drive someone around the bend" means to make someone very angry or frustrated. It suggests that someone's behavior is pushing another person to the point where they are close to losing control of their emotions or behavior.

Here's an example of how this phrase might be used in a sentence:

"Her constant nagging was driving him around the bend, and he was about to explode."

In this case, the person's behavior is causing the other person to feel extremely irritated and frustrated to the point where they might act out in anger.