#Hell includes, but is not merely, the absence of perfect happiness in God.
It is a place of despair and hopelessness, reserved for those who reject God's love even in his last breath.
But some people (many?) genuinely don't want the beatific vision in the next life. They insist they'd be happy enough without it.
That's a good reason God also provides, for good measure, the fires of hell -- external flames that cause forever-pain in both soul and body.
And even then you're getting off easier than you deserve, considering you're offending your literal Creator, who is infinitely good.
While you're still drawing breath, choose wisely.