About all this hell stuff...?

So I've seen Christians throwing around hell rather flippantly, here and elsewhere - "if you don't follow Jesus, you'll burn in hell!"

Now think about it. Hell is supposedly horrible beyond anything that we can fathom. Being there for a few seconds is unimaginable torture. I'm thinking that even if someone burned down my house, killed my loved ones and ran over my cat, I wouldn't want to punish them by making them suffer so excessively for eternity.

God's supposed to be more compassionate than me, a mere human. So (a) how can he stand to have people suffering in hell? Why doesn't he do everything he can to save them from that? (And I don't want to hear that "look at nature, God created it, that's how he proves he exists!" Sorry, a pretty tree is not enough proof to make some people believe wholeheartedly in something invisible.)

And (b) is it really Godlike for Christians to throw around hell like a cheap threat, not really caring about what an awful place it is?