Though you may not know it, the bartenders and waiter who serve you hate your guts. In fact, they have a low opinion of humanity in general, just ask them sometime when you’ve already tipped them. They put on smiles, if they smile at all, and do what they can to keep from tampering with your order. It’s a daily struggle.
Though they may take a long time with your drink, you don’t usually hurl insults at them, especially if you plan on getting that drink. A Spanish bar looks to change your thinking on that. In fact, they encourage insults slinged at their bar staff. So, remember this phrase: Una cerveza, maricon.