I've stopped tipping ever since a few of my good friends that are directors at large hotel chains told me to not tip them.

I did notice that while I was staying at Disney, my friend tipped housekeeping every day (just like $5 per day) and got her towels (+ extra towels) shaped into animals -- and it was impressive! It would've taken me at least a few hours for me to do anything remote like that (I had no idea you could make Mickey Mouse out of towels).