It may just be what I have been through in life in general, but I always tip because I think humanity in general is closer and closer to bad crisis times... and I always feel like it's necessary to try to remind people that others care, even if it is in a small way. I know you can't earn grace and you can't buy friends, but I still just can't help it because of how many times I've been in those crappy jobs. It's better than jail or lying in the hospital, but it is still tough on your mind sometimes... to be stuck in the rut of just barely scraping by.
That's why it's important, also, to work close to family and friends in times like these - being a helping pair of hands can make all the difference, especially in the lives of the elderly.
It would be nice, I agree, to have the companies who hire people to boost their esteem more, but we live in an imperfect world. No matter how trite or old it gets, it's still, sadly, true.