>>5 Is that a system in you country?
I don't think anyone is obliged to tip, and not everyone has the finincial capability to do so, does that mean we can never go eat out for a change of breath? Of course not.
And all the things you mentioned are things that are part of their job, and they're getting paid for it (even if they're underpaid) I'm not saying it allowed you to be rude to them not at all, treat everyone nicely and with respect, but I don't have to tip, if sometime I've got extra money and tipped that's alright but if I don't have then I'm not obliged to, unless the store made it clear tipping is obliged for the meal.