I have done the same as well. I'd rather do the "take this to ____" than "go get me this from ______." When everyone was on floors 1-3, I'd go to whoever was in the dining room or the clock room (or when Eduardo was in the bathroom next to Mr. Herriman's office). Now I just go to Mac, since he's the closest off the elevator.
At first I thought it would affect gameplay, depending on who I did favors for. So I did everyone equally. That lasted about a month.
~Vicks