I was biting the finger nail on my little finger and nipped the the top of my finger by mistake and it hurt like f**k
I think that's about the worst pain you can get though, really kills. I can't imagine that biting your finger off would be worse
you'd have to do it as far from the nail as possible though as sensitivity decreases. there's loads of nerves and feely things at the pointy end so we can use our sense of touch efficiently and not so many at the other end cos they'd be wasted