I am sorry. I hate it when i have to do this, because i know that it's really silly! But the only reason why i wouldn't fan anyone back, would be if they had joined the twilight saga club. I can see it on their perfil and i immediately go all prejudice against them.
I shouldn't, i know, but it's against my morals to fan someone who loves the Twilight saga. If you're only a fan of Twilight, sometimes i forgive you... if you've done something to earn my respect.

Which would lead me onto my siguiente reason...
If tu have done nothing to earn my friendship, and not joined any of my favourite/major clubs, then i don't feel obliged to fan you.
However, if i can see that you're a fan of 'Random' o 'Harry Potter' o 'HP v T' etc, then the probability is that i will fan tu back.

On the other hand, if tu are looking at this thinking that tu haven't done any of these things, then feel free to fan me... i'll gladly return the favour! :)
xxx