Because for the longest time, we lived in tribes. If you got thrown out of your tribe, that was essentially a death sentence.

You did very well in asking this. You are very clever.

What is the point of being self-aware if the only thing you are aware of is your inadequacies and failures? We need validation in order to keep going.

A desire for approval drives social creatures towards pro-social behaviour, which can positively influence the sucessfulness of a species

Social beings like approval of peers.

Like another commenter said, survival instinct.

Also its a nod to our identity, we derive a sense of self worth from those around us. Approval from people who believe what you do makes you feel like youre a part of smth bigger than yourself (look at religion, nationalism etc).

I don’t actually like validation, recognition, or getting compliments, but I somehow feel slighted when I don’t get them and think I should’ve.

Your question is wrong. Few if any people need constant validation. The question is what frequency people desire it, and how, and that varies greatly by person.

Because we’re a social species that often checks ourselves off of those around us. Sometimes it’s unhealthy, but often it’s an attempt to maintain tribe status and to safeguard against misperception.

Some good answers, but I also want to point out that this isn’t actually a universal need.

I think that our social nature, and the way most societies and communities work (particularly in countries that subscribe to exceptionalism) makes them prone to developing these feelings, but they very much are not universal and can even be unleaned.

People generally need some validation but I think you’re making an inaccurate generalization