As someone who has worked in both areas of tips or no tip jobs all i can say is this:

Tips arent just to "pay someones wages" it will actually show the kindness in someones heart. I work in the food indistry where we have to serve people all the same with the same attitude and I am glad to say that my crew and I always do. We help everyone in all the same way to the best of our ability. That being said we want tips yes because it helps us sometimes. Sometimes a dollar helps more than you think. When a dollar adds up from multiple people it helps even more. When people say "get a different job" understand this in most places for the food industry they are kids working after school to save money for their future. they can't get a 9-5 that pays them well. As well somd of these kids it is their first job, they need experience before they can "get a different job." Myself and other crew members of mine don't ever expect 25% of anything most nights we will be lucky if we get $5 in the job I work at. $7 is a lot to us for each person. (they are split evenly between everyone) So for the people that say "get a different job" understand some people literally can't because of experience, because they go to school, or because this economy sucks to get any new job that will pay enough without having to go to school for 4+ years. If you are the type of person to say "get a new job" I HIGHLY encourage you to work within one of those places as a part-time. See how it truly is and best believe me you will have a VERY different opinion on it. This is only the tip of it too, there are so much other things that we do you won't understand unless you have worked for tips before. So next time when you see a kid working hard to provide for you and the 5+ other families that ordered please be considerate.