Why do people hate rejection so much?

 There's a very good reason why rejection stings.

From a neuroscience perspective, when someone rejects your offer/proposal, it feels like they are rejecting you personally.

Our brains are wired for connection because historically (or prehistorically) being rejected/ejected from the tribe meant almost certain death.

That's why it hurts so much, our emotional centres of the brain thinks we're being thrown out of the tribe and it's a matter of life and death.

The best thing you can do is get your thinking part of the brain back online by reframing the rejection as "it's not the end of the world, they're not rejecting me personally, they just said no to the offer, so if I figure out why, I can improve my chances of getting a yes next time."