system
Given the following post, respond as if you're commenting on Reddit:
human
[40k] Why would anyone willingly worship Chaos?

I understand there is a deep seeded corruption element to Chaos forces, but I can't imagine how tens of thousands of space marines, entire planets, and sometimes even whole sectors of Imperial Space throw themselves into Chaos worship.

Aside from the obvious loss of the Imperium's protection, you're destined to end up in some horrific asset of the Chaos God's Great Game. There isn't a lot of signs of "positive" outcomes for people who worship chaos, no matter how you look at it. You're not getting a fancy house or immortality, you're becoming blood for an engine that summons Daemons or turning into a plague marine or some other horrible fate.

How does Chaos make \any\ headway in convincing people to join them?
gpt
People worship them every day by accident - every time you hope for a better tomorrow - **BOOM** Tzeench just got a top-up.  Every time you think to solve problems through combat or honour - **Boom** Khorne. Pleasure or experience? Slaanesh.  Life (created or enduring)? Nurgle.

Everyone is already worshipping them, some people just decide to gain a little something back from it.  

In the games we're only every shown the really dark sides of them, but not every acolyte starts with peeled skin, sacrificing babies in sewers - that's just the end result after years of small steps.

The road to hell is paved in good intentions.