I'll give him a dirty look like in the OP.![]()
However you also need to add the threat/extortion element. If he doesn't venmo you you'll make fun of his posting style and troll his threads, for example.

Your picture illustrates a good point. If you're going to tip, you might as well tip at every stage of the supply chain. 15% tip for the fisherman who caught the fish, another 15% for the boat driver, 15% for the distribution, 15% for the chef, and then a 15% for the waiter. Why not another 15% for the restaurant manager for keeping the place nice and clean. Hell, add another 15% parking tip since there was space in their parking lot. Might as well tip robots too. Oh wait they already expect the last one.