I like to be generous, but 22% is more than enough for a tip. That's more than 1/5 of the bill!! I might even complain and force them to take it off if service was bad. I'd much rather have a "mandatory" tip of 10-15% and then add on something.
However, I've also appreciate good service. I will tip above and beyond the suggested tip for staff that bring my room service order right away, make sure the food is hot, or bring everything in one of those nice combination food warmers/tables on wheels. I'm addicted to those.
