I'm going to throw away customers food
What made you decide to throw away their food?
The customer was not polite to me.
Rude customers can be difficult to deal with, but you can't just throw away their food before they're finished. You wouldn't want to waste food like that, and you'll likely get in trouble from your boss. Just do your best to stay polite until the rude customer leaves.
I am still gonna throw their food away.
I think you'll get in a lot of trouble if you do this. You should reconsider.