A wage is what an employer pays to their employee in exchange for the work that they do on behalf of that employer.
A tip is something provided voluntarily by a customer over and above the actual amount due for services rendered or for goods, food, drink, articles sold or served to them.
So no, nobody automatically "deserves" a tip or gratuity. Like the wage itself, it has to be earned.
I spent a lot of my youth in the restaurant/service industries as I worked my way through high school and college. I tend to be extremely generous and usually over tip as a result. But make no mistake, in the event that the service sucks, any tip can certainly reflect that.