Ever have that one friend who never seems to return calls and/or texts? At first you think, oh they're just busy, but as time goes on you begin to realise something is amiss. You realise that you always seem to be the one to initiate contact; it's rarely the other way around. When plans are made to meet up somewhere, that person is usually the one to break them at the last minute, and they break them often.
But what is odd is when the two of you are together and talk, both of you honestly enjoy your time together, and you have great laughs together.
So what gives? Do they regard you as a backup if nothing better comes along? Are they just plain lazy when it comes to interpersonal relations? Do they feel insecure in some way?
Why push away someone whom you obviously get along with very well? You must realise one day that person won't be there for you when you deign them to be, because they'll be tired of trying to be your friend.
Friendships really don't take a lot of energy to maintain. It isn't like you need to be constantly around - just say hey, how's it going once in a while, or answer back. That's it.