The difference is probably at least partially cultural, but probably not due to some kind of a single factor such as "responsibility". I'm not from Norway, but

The difference is probably at least partially cultural, but probably not due to some kind of a single factor such as "responsibility". I'm not from Norway, but other European countries also have systems that are more or less similar. Where I live, I think most adults would find it socially rather unacceptable to abuse a sick leave, at least on a regular or systematic basis. Getting caught would be rather embarrassing. So there's a social stigma against abusing the system. (That's probably not true of everyone, and there's always somebody abusing the system, but I believe the majority would find it socially unacceptable.) Another related difference might be that at least in Nordic countries, people place more trust in the system, and the balance between collectivism and individualism tends more towards the former. If the system is seen as more trustworthy and as more of a mutual thing, as opposed to something that everybody's trying to game anyway, cheating the system is then also less acceptable. It would be like stealing from a common coffer. (Of course not everybody sees it that way, but I think there's more of a tendency towards that in the culture. And practically nobody who's not entirely naive trusts the system unconditionally, nor should they. But many ways of gaming the system for your own benefit are less acceptable to most people than they might be in a different culture.)