Rik, you added those last two lines on your post after I read it, so I couldn't respond to it before. When I said everyone, I meant everyone in America. You don't tip in the Netherlands, so it's understandable that you don't know, but it also doesn't pertain to this conversation. Everyone who lives in a culture where tipping is expected knows to tip, and they know that tipping should be around 15%. There are those too cheap to do this, and there are those who object for other reasons, but that doesn't change the fact that in the US and other tipping countries, everyone knows, and thus it is not a hidden cost.
Referring to the exact change thing:
That is the norm.... ... .. nowhere
I don't care where the norm is, no where does it state that a delivery boy is required to carry exact change with him. The store might do it out of policy (customer satisfaction) but no where in the US is it a law, no where can you call the police and complain that you were robbed of twenty cents because you couldn't get exact change. If it's that important to you THEN FOR HEAVEN'S SAKE, GO TO YOUR CHANGE BOX AND MAKE THE EXACT CHANGE YOURSELF. YOU ARE IN YOUR OWN HOUSE AFTER ALL.
If you're too lazy to do that, then as Bug said, if you don't want to be short changed, then the delivery boy will just take the pizza back. He has no obligation to sell if you don't pay up first.
Because they get paid well = no need to rely on tips.
But they would get paid well even if they didn't do a good job, so where is the incentive to work hard? On the other hand, if you have to scramble to earn those tips, you WILL scramble, and do your damnest to make the customers happy.