I've had one such friendship. At first I really didn't care for him, I had cast him in a project but his audition didn't impress me. He kept showing up to any event that I sent mass invites too as well as volunteered for horrible roles in various projects I or a friend would produce. He was even willing to do roles where you couldn't see his face as he was wearing a costume. After that night I felt bad that he tried so hard so I invited him to my place to film something I had written specifically to show off whatever talent he might think he has.
I was so blown away by his performance, it was nothing like I had seen in his auditions. It wasn't some Oscar worthy acting, don't get me wrong, but it was real acting and something he clearly worked really hard at. His process was such that he needed to build up the character in his mind, come up with back stories, histories, quirks and flaws and hopes and dreams for the character, something you don't really get an opportunity to do in an audition.
After filming, he just spent the evening in my apartment, looking at all the artwork and trinkets and asking about each of their personal stories. I began to realize he was genuine in his appreciation of others, it wasn't just some mask that most 'actors' put on in order to seem appealing. He learned things about me that night that most people can't really understand let alone appreciate.
We ended up producing an entire feature film together. We went on many adventures together such as trapeze classes and hikes to hidden hot springs. He took care of me after a low point when my father died. He helped me maintain my sense of self after my mother ripped it out from under me by revealing that a tragic event in my childhood that really molded me as a person was something she had orchestrated.
He has since moved away to pursue a masters degree, but I miss him. I write a letter to him every month, I just dropped the most recent one off at the postal office an hour ago.