You're not wrong, but it comes down to delivery. I've said a lot of bizarre, goofy lines in my time, in various stages of social aptitude. The same line comes across very differently based on whether it's said confidently with a self-assured smile, or muttered while looking at your shoes.
This is my problem, I am impulsive and silly enough to still say things, but the way they come out sometimes makes me want to die a little inside and stop being perceived forever.
Sometimes if I am not doing too badly I still can turn it around, where the very failure of delivery can on its own get the laughs (or groans). If I sort of stay with it long enough to express something like "yeah, that was bad wasn't it? want more?". But it does require a minimum of social aptitude like you said, which for me varies a lot.
Anon is locked into self directed attention showing him his shame when considering that there is a whimsical part of himself known as the chocolate man inside himself. Why this makes him ashamed is not specified. I speculate that there is a belief that if other people knew he would be the subject of ridicule.
They're just trying to have a casual conversation, as long as they aren't trying to offend you it's fine. It's shit treating staff like an eftpos machine and not acknowledging they are human.