That taste of inadequation

I am not good at making friends.
I am very judgemental, and therefore very selective. I have little time and even less emotional energy.
So I shouldn't actually mind not having many friends because it means that the small number I have I can actually take care of.
And I do try not to mind.
I don't see them much but I think of them and send them trinkets and postcards and messages to show them I care. I don't know how to sustain a conversation so they often die out.
I have been trying to be more sociable but it doesn't seem to work really well.
I'm afraid I sound shallow.
Or too eager.
I don't know.
Why do I care so much, when I am not even being a good friend to the friends I have?
It doesn't make any sense.