Most people don't like to feel stupid. Most people will angrily defend a stance that they know is wrong, but admitting fault is beyond their capabilities.
There is also a reasonably large portion of the population that don't like smart people telling them anything because they view it as said person talking down to them because they're smart. It's a matter of pride. As can be seen in my signature, Pride is the Enemy. No one is perfect, but they want everyone to think they are and admitting fault would be an admission of lack of perfection and we can't have that now can we?
'Murica in a nutshell: "You're using a lot of really big words that I don't understand so I'm going to take it as offensive." ~Kevin Hart, 40 Year Old Virgin.
and this is the problem....ego. Not enough people ever grow up enough to get over their ego.
when i was a kid, I quickly learned to "get over myself" from my dad. I was told to "shut up and listen". Assess a situation and ask questions before reacting or determining a path. And then, if you make a choice, go down the path, and find out that it is the wrong one, stop, reassess, and make a new decision or path. Also, I was taught to "admit defeat" and regroup. I was encouraged to fail, but also discouraged to wallow in my pity or fear of being wrong...
now, dad was a bit more short with his words since it was the 70's, and was a Marine Corps drill sergeant in the 60's..with phrases like " I told you so" or "suck it up dummy" and "don't be a whiney p**sy" ( and other more colorful ones) carrying a lot of hidden meaning.
Ego...pride...for the wrong reasons are the downfall of many great things