Those in control of the clinics... are the ones who view this generous behavior as negative. The lower nurses, they are not in control of your case, so they probably appreciate something. Remember, drug reps have started this habit, of bribing doctors to prescribe. I think this plays into their feelings as well.

Its never nice listening to doctors like I did, complain about their patients.
How those patients "abuse" them, call them at all hours, demand pain meds...I heard it all. It was not nice. But that is what is going on behind the patients' backs!

When I had my son, and was in the hospital for 6 days, I bought goodies for the nurses, when I LEFT... that type of gift is a gift, since you are not hinting at a future payoff. Many people do this... and I think that is different upon discharge.