Why does evil exist?

I was amazed that so many people thought this was a valid answer.  If that's the case why does good exist? Because evil exists, duh.  Circular logic like this is illogical.

It's the same reason you can't say God exists because the bible say's so.  Why trust the bible? Because it's god's word. Dduuhh... Or the trans debate.  A woman is anyone who feels like a woman?  Define women? Anyone who feels like a woman.

So if evil doesn't exist because good exists then why does it exist?

Those that commit astrocytes rarely see themselves or the acts as evil.  Unless they're psychopathic.  Even when they agree that they may be bad they justify them as necessary for a greater good.

Have you ever commited an evil act?  Why did you do it?  Does that lesson the evil that was done?  Would an outsider see the act in the same manner as you?  Noone see's themselves as evil.  Only good people who sometimes have to do bad for a greater good.

It's our consence.  The angel and devil on our shoulders.  And I'm well aware this sounds far crazier than 'evil exist because good exists' but hear me out.

Good and evil are what we label actions and thoughts that lead us towards or away from the best future. You might be thinking being selfish and evil would be the best option.  Screw everyone else and end up on top.  If you manage that then evil will become good, right?  Wrong.

We are social creatures.  That's why we enjoy going to restaurants, the bar, cinema etc.  We can all do these activities for far cheaper at home, but we choose over and over again to pay more to be with strangers.  Why?  Because it's good.  A lonely king isn't something we should aspire too. It may not be evil, but it's a bad future to aim for.

The idiot sees the world as Good vs Evil. The cynic sees the world as Evil vs Evil. The truth that no one seems able to see is that the world is, and always has been, a battle of Good vs. Good. - Norm MacDonald