I briefly worked at a small phone repair shop that didn't see much foot traffic or get many calls, but we also had a mandatory line to say when answering the phone. I don't remember the line, but it was a little more than "thanks for calling X, how can I help you?"

Anyway, once I was very tired on shift and got a call, but totally butchered the line, messing it up immediately, then correcting myself with plenty of "uhm" and "sorry, I mean ... " added. Eventually I realized there was no recovering, gave up and just stopped talking. After that there was a long silence, followed by the sound of someone laughing their ass off.

Turns out I was fortunate - it was my then-girlfriend calling, rather than a customer or manager or something. When she stopped laughing she said "do you want to try that again?"