I need to get out more

More often than one might think, I find myself in an interesting emotional exchange with someone else characterized by one or more of the following:

a. codependence
b. drunken and dramatic conversations
c. consistently inconsistent communication initiated almost exclusively when some problem has arisen
d. renounciations of friendship followed quickly by pleas to reengage
e. awkward confessions (of any sort)
f. complete and utter failure surrounding the concept of reciprocity

All of these particular friends have one thing in common - the fact that at some point, some version of the following statement has been uttered...
"You understand me like no one else can. I feel like I can talk to you. You're great."

That's nice. That's wonderful, I imagine. Here is where my problem with this series of men surfaces::

If I am so great and/or important to these people, why don't/can't/won't they act like it?

Are we friends because I genuinely understand these people or just because I'll sit down and listen? Do I need someone to need me so much that I will put up with this? Again and again? Is this phenomenon, for the most part, my own doing? Are all of these men really my friends, or am I just a glorified counselor? Am I destined to relive this somewhat pathetic codependent exchange with every interesting guy I meet?

I have been perplexed for years.
Feel free to submit answers.