A good example of stupidity is how OPL thinks the real world works similar to cartoons.
Stupidity is being disconnected from reality in a similar fashion.
Webster defines stupid as "a lack of ability to learn and understand things." Such is an apparent symptom of lolcowdom. The stupidest person of interest would be the one who embodies that definition the most.
@ToroidalBoat That's the best way of putting it, the inability to learn.
Not knowing something is just "ignorant", but, continuing to not know it after encountering it multiple times, that's stupidity.
The fundamental essence of the cow is trying the exact SAME approach to get a perceived reward (money, sex, whatever), failing, and then trying the EXACT same approach AGAIN and again and again, with little or no change at all. If they DO change strategy, it's a meaningless change... like "They didn't accept my hand-drawn $100 bill! Bah! I'll use PURPLE crayon this time!!!!" Even when they DO finally catch on the plan isn't working, they fail to see WHERE it's going wrong.
That's stupidity, doing the SAME thing and expecting a different result.