Personally, I never EXPECT a tip.  It is always VERY much appreciated, of course but I NEVER expect nor think badly of a gentleman who doesn't tip.  
My neighbor once told me that she never tips at her nail salon because their rates are what their rates are.  I always generously tip my nail tech because I'm sure they don't make much per hour either PLUS they do a very nice job!
I guess I tip generously in general because I just think it's the right thing to do.  Of course, we here, make a bit more than the general employee in public jobs.  If you tip me, I will love it and appreciate you very much.  If you don't tip, I will STILL appreciate you very much!  
This is MY thought...  
 
--v