I think the answer is Political Correctness, which has traumatized a couple of generations now and robbed us of some of our choicest humor.
I presume the people in the elevator were strangers. Your friends and associates know you and know this is not your customary behavior, or else they know it is your customary behavior, but in any event they know you. They see mowens wearing a chicken hat.
The strangers on the elevator do not see the same thing that your colleagues see. “You” don’t have any special significance to them. Instead what they are looking at is an instance of aberrant behavior: inappropriate workplace attire. They are seeing a chicken hat on some guy, which is an altogether different thing.
At one time they might have just laughed spontaneously. But now we are conditioned to accept anything we see and not take any chances on being called judgmental or on inflicting a blow on someone’s self-esteem. After all:
— What if you didn’t know you were wearing a chicken hat and they didn’t want to call attention to it?
— What if it had to do with your religion?
— What if you were crazy and dangerous?
— What if you had been condemned to wear a chicken hat for unimaginable reasons and were very sensitive about it?
— What if this were somehow an experiment, a test of them?
The worst sin these days is to offend someone. If they had laughed, they would have risked offending you. That would be a serious offense in the workplace of today, worthy of HR intervention. The safest course is to be politically correct about it: to act normal and pretend not to notice.
It would be interesting to perform this experiment with some controls: reaction of friends not in elevator, reaction of friends in elevator, reaction of strangers not in elevator, reaction of strangers in elevator. After all, you don’t know which variable—being strangers or being in an elevator—was the crucial one here or whether it took both. (I want you to try it with the hat that @erichw1504 found.)
They probably laughed once you got off, but only to people they knew and trusted. You never know.