You can accuse Janne Teller of a lot of things, but being warm and fuzzy isn't one of them. The characters in Nothing are so cold that if you licked one of them, your tongue would get stuck.
An example? Check this out. When the gang is pressing Huge Hans to give up his bike, Agnes says, "Sofie was one of those who pressured the most." (12.16) The only line on the next page is, "She shouldn't have done that" (12.17). If that doesn't send icy chills of foreboding up your spine, nothing will.
Why so cold? Well we've gotta say, these characters are ice queens and kings if we've ever seen some. We've got Pierre going around proclaiming that the world has no meaning, and a bunch of other budding sociopaths demanding severed body parts like it's a game of truth or dare. These people aren't exactly bursting with empathy. Their moral compasses are faulty at best. And because they're slowly arriving at a belief that meaning is, in fact, nothing at all, well their insides are of course cold to everything around them.