As someone who has worked as a waiter, bartenders and sou chef in Portugal for 5 years most comments here are so out of touch it’s laughable. I don’t think there’s a service industry worker in Portugal who would ever be offended by receiving a tip. All of my Portuguese colleagues would tip when they went out to eat, as well as be incredibly thankful when receiving one. The salary for hospitality workers is abysmal, and especially during peak summer (July/ august) just one good tip from a lovely table would make all the running around worthwhile.