If you think that about that way....familial bonds are almost stupid. Lavished on people just because they share a set of your genes in some percentage and because you've been forced into close proximity over the course of years. You might have the same mailman for decades yet never feel any tinge of affection for the man other than when he hauls a particularly heavy package to your door without breaking the contents.
Friends can leave you by the wayside and lovers and husbands and wives can abandon you. But in the end, there's always family whether you're sure you deserve it or not.