Service with strings attached

Last night Rod and Robyn went out to eat with her family to celebrate some February birthdays.  On the way home, her cell phone rings.

Robyn:  Hello?

Nate:  Hi Mom! I just wanted you to know that I walked the dog, emptied the garbage in the kitchen, and cleaned off the counters.

Robyn:  Wow, Nate!  Thank you so much!  It makes me so happy when you do things without being asked and without expecting anything.

Nate (after a long pause):  Well, I think you're going to be disappointed then because this isn't one of those times.