Shut The Door

You say you know what's good for me 
But you are the worst thing I think I've ever seen. 
And if you really want to do a favor for me 
Get out of here right now, do you hear me? 

I don't want you anymore 
And when you leave please shut the door. 

If you really want to do a favor for me 
Shut the door when you leave 
Because I wouldn't want you walking in 
And see me messing around with my new girlfriend