Only once. In Florida on a mangrove flats Snook trip. The guide was pointing to snook under the shadow of the mangroves and we were casting to them. We weren't seeing a lot of fish and I wasn't good enough at casting long distances to them. The guide started getting really pissed at my casting and frustrated that we weren't seeing fish. My dad had to tell him to calm down once and that it was just good to be out fishing. He didn't speak a word to us on the way back in and yelled at me to "tie the $%&# boat off" at the dock. We had prepaid, so we just packed up and left without tipping. I felt it justified.
As far as the GSMNP guides, there are a handful of them that can't be beat as far as experience and friendliness goes, so don't get discouraged and give up on them.