Blood and Soul.

If you're somebody, like me, who's grown up away from your homeland, and rarely visited it, you probably agree with me when I say, "Relatives are like lottery tickets. The emotional outcome of your meeting with them, is as random as the result of a raffle draw." [Aaand if you're somebody from my extended family, you probably hate me for saying that! =D ]
It's a funny concept really, the whole assumption that relatives are afterall more deserving of our love, than other entities like 'neighbours', 'family friends' and buddies in general. And the main promoters of such esteemed thoughts are called the "Auntyjees", in the Indo-Pak Society. The exact definition of these Auntyjees is: females who's existence you discover one fine morning, back home, when you wake to their affectionate "Aslamaliiikuuuuumm!" followed by the-cheek-pulling-ceremony, where the lady checks the durability of foreign cheeks. Their most distinct characteristic is the surprise at how much you've grown from the tiny body running around in diapers. Talk about the lack of expectations!
Studies show that 9 out of 10 Auntyjee's suffer from heartbreak due to the strong bonds between their distant-nieces/nephews and people from outside the family, which the Auntyjees fear effects the nieces'/nephews' priority list. (Okay, there's no real study like that but I bet that would be the result if there was one.)
Now the aim of this post is not to diss family bonds but only to express my view of them.
To me, the essential difference between relatives and loved ones is that of blood and soul. Blood is necessary to survive, the Soul is needed to live. Once your born, you necessarily have some relatives. But if you live a life worth living, you most definitely have people you love.
Who makes it to the top of your priority list is, honestly, less in your own hands and more in the hands of those around you. Yes, the immediate family - your parents and siblings- deserve an unmatched place, that is unquestionably a fact. Above all, of course, the beloved Prophet (SAWS) and our innumerable religious mentors.
But in terms of society, as a strong contender of 'true relationships originate from honest affection', I believe it really isn't in our hands to choose who shall be that genuine with us. Only our definition of 'genuine-ness' comes into question again ..... but that's a different post. ;)
The importance of understanding this lies in realizing that we need to stop taking those around us for granted -  not only in terms of our natural relationship with them but also due to our spiritual connection that they have established with us, be it a sweet neighbor bringing you chicken soup when you've cold or an aunt buying you candy when mom's not looking.

Summary of the above mental ramblings:

"You can stop the Heart that pumps Blood but you can't stop the Soul that spreads Humanity."