There's more than one answer to this....on one hand, it could be someone who simply wants to prove themselves as being an intelligent person and the best way they can think to do that is to make others look stupid...on the other hand, perhaps this person was raised this way - constantly being corrected, to the point where they don't even realize they are doing anything wrong when they do it to others.
It may be the only way they feel better than anyone else. They typically have a false sense about themselves. I feel sorry for them since they have no self awareness, they will never really experience the mental growth or true friendship they would otherwise.
This is really bad in marriages and is a sure way for women to emasculate their husbands. Correcting them in public or in front of his friends, coworkers or the kids is a bad thing.
They have a low self esteem, and makes them feel better to make others feel low.
sometimes they do it to feel smarter or accomplished they noe something u didnt
to make you feel stupid so they feel better about themselves
I have know idea but think it is incredibly irritating.
To try to be a know-it-all show-off.
because they feel the need to
They like to look smart.