I've been chastised on-air twice (that I'll confess to) ... both were actually positive experiences in the end. 1) Center controller got irritated that I had multiple approaches/airports on a single flight plan (as is customary for Approach controllers in the area). I kept my cool and he finished his venting, but I later called Center to ask for clarification/education. It turns out that Center and Approach didn't know they were doing things differently between them, and they spent several days investigating to improve their service/understanding. My only regret is that I flippantly said he "chewed me out", which set a conversation-tone I hadn't intended. 2) Departing IFR, tower gave me a clearance amendment just before I took off. I complied, but then got chewed out for failing to follow the original clearance. I simply told them what my instructions were and didn't worry. When they handed me off, I asked if I did anything wrong, to which they replied, "nope, our mistake". I'm still pretty impressed with the US air-traffic system ... 99.9% of the time it works without issue, and for that 0.1% of issues, they're quickly/reasonably resolved 99.9% of that fraction too.