Things I worry about

The unanswered question that has lived with me for about 32 years: At what point do you give up or when is enough enough -- time to stop?

I'm bummed. I've called a "friend" a couple times and emailed but they haven't gotten back to me. I know this person is busy but I also know they are communicating with other "mutual friends."

Usually this question comes up for me in my relationships with various people. I have come to accept that I have extremely high standards for myself as a friend and I expect the same from those whom I call friend. I am hard on other people but I am doubly hard on myself.

My global observation of my life to date is that I tend to care a lot more about my relationships with other people than they SEEM to care about their relationship with me. It seems to me the work of maintaining the relationship falls more to me than the other person. Meaning, if I don't call, or email the other person isn't likely to call me. I am always going to someone else's' home they don't offer to to come to mine or find reasons to decline. If, when moving, I don't ask for a "friend's" new address or phone number they pretty much "forget" to give it to me.
[A real life example and a pretty big hint I'd say. The follow up is that after 15 years this person was having a celebration and wanted me to participate. They made no effort whatsoever in 15 years to even send along an internet joke but suddenly I'm needed at the celebration. Hmph.]

Sounds crazy right? I know. I agree. I agree so much that I agonize why someone may not have returned a phone call or sent a Christmas card--worse yet sent a card late. Are they--have they--just been polite the whole time? Have they been seeking a way out of this relationship the entire time? OR is it more likely they are just busy and distracted with more immediate concerns?

Sometimes I'll just ask "are you just busy or have I upset you in some way" The thing is I don't often trust the answer. If you have been secretly wanting to get away from me are you going to be honest and tell me so or are you going to say "oh no I'm just really busy with work/family/whatever" More often I don't ask, I just stew internally imagining what people really think of me and just won't say out loud hoping I'll clue in.

So, when do you know that you care more about a relationship than the other person. What clues you in that your friend isn't really your friend just a friend-LY acquaintance? How long do you wait for a response to an email or phone message or letter before moving on?