the problem with this story is that we cant know the real truth because that is only one part of the video, where is the part where he delivers the pizza? it is a security camera, so, where is it.
in this article and other articles
http://www.dailymail.co.uk/news/article-2911009/The-Internet-bro-Car-dealership-cruelly-shames-pizza-delivery-man-taking-away-tip-posts-video-backfires-spectacularly.html
"Making the entire thing even more cruel is the fact that they gave him two twenties and two fives on a bill of $42, making it seem clear that the extra money was for him - something he even confirmed with the workers."
it is said that the extra money was confirmed to be the tip
but, in the video that everyone has watched, why the delivery guy doesn't mention it?
maybe in america, if you receive an extra bill it means, keep the change?