Why do we put up with this?

Lately, I've been asking myself why we - as nurses - put up with so much crap from patients and doctors alike. We work our tails off, take care of everyone else, and get treated like we're expendable. Today, I had a patient scream at me because their dinner was late. Later, I had a doc treat me like his personal secretary. I'm just...I'm just tired, you know? Why do we continue doing this to ourselves?