OTOH, there are times when you WANT the agent to note a conversation in your PNR. One time, there was a schedule change and the agent couldn't find a suitable schedule. She offered a refund, but I had to double-check the internet to make sure I could re-book the flight for a similar fare (back in the days of dial-up internet). I gave her several minutes to document the record and was extremely pleasant.

As it turned out, I rebooked my trip on another airline for less than I had paid originally. I called back and the agent had notated the PNR correctly (so my refund was processed).