Yeah if i've been drinking i won't give a stuff and just order delivery.
It's mostly just principle. I hate tipping in general because it's just subsidizing a company's employees under the guise of a reward.
Audaciously enough, many places call it 'expected gratuity' and mandate tips or take it from the bill automatically.
I don't have any problem with tipping because it shows appreciation towards the person who served you. Like, this guy dealt with all the stuff to get past the front desk man and come up the elevator and find my door, so I don't mind giving the guy a few bucks (not usually five though) for going through the hassle. I'd rather give it to him where it goes directly to him rather than pay the restaurant extra.
Regardless, though, the concept of 'expected gratuity' is ridiculous. I can't believe that a pizza place would have the insolence to say that they expect you to tip.