Only time I have tipped a receptionist is to get an early appt with a doctor at a specialist office for medical care. I give them $100 and ask them to fit me in ASAP. Usually get in with 1 hour or in the next 2 days. Much better than waiting 3 - 4 months as the other patients do. Doesn't work all the time, but when it does, it is a life saver.
And don't hate me for doing it. Americans who come across the border can see a specialist in Ontario that same day. So, it isn't fair that us Ontarians have to wait months while visitors get faster treatment because they are allowed to pay and we aren't. Bet you guys didn't know that.