The one huge contradictory thing I can never get over - among many - and that no Christian I've ever spoken to has ever managed to waffle their way out of is this:
Heaven is supposed to be the nicest place ever, where we all live eternally in god's ever loving arms etc etc.
If I become a fully paid up, happy clappy born again tomorrow, I go to heaven. Where I'll be blissfully happy forever, right?
Only I'm the only born again in my family. The rest - my DH and my kids, and all my friends are NOT religious in any way. So there I am, toodling around heaven, knowing that the people I love are burning in eternal agony.
But I'm going to be able to get over that am I?? 
Doubtful. So there I am in heaven forever, tormented by the idea that I'll never see anyone I love again and not only that - they're suffering.
Yeah heaven sounds lovely 