My wife and I both will give compliments to good workers. Going so far as to track down the manager and telling them that such and such cashier was exceedingly nice or what ever.

We also don't hesitate to call and complain if we get bad service in a restaurant. One thing I always make sure to do when complaining to a restaurant is decline what ever freebies they offer. Sometimes going so far as to tell the manager I don't want your free appetizer to get me to come back in I want the problem fixed. I've worked in various food service jobs long enough to know that most complaints are scams to get free food. I want them to know I'm not after their food I have a legitiment complaint.