That is, concierge employees, cleaning staff, bellmen, servers, valet, etc.

I've been blessed with a goodjob and a nice income. The people that serve us usually aren't all that well off and most do try to help us and make our experiences better where ever they are serving us. To leave a little bit in thanks can help their lives (especially if done by many customers) and doesn't greatly detract from my life so why not?

It makes me a little sad when people say they just don't believe in tipping or don't understand (or care) how it can effect those less fortunate than ourselves. I read a book called "Nickled and Dimed" where the author worked several low paying jobs and tried to live for a few weeks on the money. Her struggles and the impact of the tips her customers gave her helped to opened my eyes.