Originally Posted by mineistaken

It is not a stupidity that you describe for the most part. I there is some unusual door exit system (even it is written) many smart people will get confused as well.
Same with finding a till to pay.
I can assure you that if you made IQ test of those people you would find that some of them were even close to the genius level. And on the contrary you would find that out of those who opened the door or found the till quickly some would be of very low intellect.