1. Never turn your nose up at your plate
Make sure never to comment if you think your food is disgusting or it appears uneatable, no matter how unappetizing you truly find it. In most scenarios, the dish you picked and was served is a piece of regional pride and tradition. Therefore, if you really cannot make yourself to eat your food, insist that you have already eaten are not hungry anymore.
2. Do not ask for butter
The restaurant will either not have any, or in a best case scenario, they will give you margarine instead. If you really want something to serve as a moistener for your bread, go with olive oil. You re in Spain after all, and this is a local product, plentiful and even more healthy and delicious.
3. Do not eat too early
Getting the timing wrong is one of the biggest no-no’s with food in Spain. Trying to eat an evening meal anytime before 9pm is weird in Spain, and people will give you looks. In addition, do not attempt to sit down for lunch anywhere before 2 o’clock in the afternoon.
4. Do not rush your meal
Meals are and should be treated as social occasions to savor and enjoy with the people dearest. Therefore, there are no eating sandwiches at your desk. What is more, get ready for strange looks if you unwrap a bocadillo on the bus or metro, or strolling down the street. The latter is the weirdest in Spain.
5. Do not compare dishes to those at home
Remember that jamon serrano is undoubtedly superior to the Italian prosciutto, and that for every French cheese, there is a better variety in Spain. In addition to these, if you love Scottish black pudding more than the morcilla, just try to keep it to yourself. Do not mention Italian olive oil or French wine at all, nor anything similar from other countries.
6. No doggy bags
If you request a doggy bag, you will get a quizzical look, possibly an inquiry as well into what breed of dog you own. This practice is not what it is elsewhere in Spain, and is has not caught on yet.
7. Take it as it comes
For the love of god, do not dare to modify the served food in any way whatsoever. You will get away with adding more salt, but even asking for pepper or, god forbid, ketchup, the waiter will put you on the blacklist. If you wish to change the taste of a home-cooked meal, you may even insult the cook. Eat the food and compliment the cooking, that is it.
8. Do not sit down to eat tapas
This bite-size snack is almost exclusively eaten while standing at the bar, with a drink in your other hand. When you eat this slice of tortilla or a boiled prawn, make sure to wipe your mouth with a clean paper serviette, and throw it on the floor, as this is still a custom.
9. Do not over-tip
Spanish people like to tip for the service, but they do not always do it, and they never do it too much. In Anglophone countries, people traditionally add 10% to the bill, but Spaniards only leave a few extra coins, and only if they think they have received exemplary service.
10. Do not make this mistake
This is a short but important one. When you want chicken, do not ask for polla (penis), but pollo (chicken).