Great stories everyone! Its so awesome to hear about and think back on these kinds of pivotal moments in our careers.
I have a few moments like this, as I'm sure we all do, but first and foremost interning at Pro-Sound in NYC was a complete eye-opener. I had been working freebie craigslist jobs to gain experience (with a friend's gear consisting of an FR2 and some G3s) and essentially reinventing the wheel about how to do location sound! Being around all the experienced pros who come in and out of Pro-Sound, as well as the super knowledgable PSS crew changed my perspective entirely and made me realize the "right" way of doing a lot of things!
My second moment was the first film I boomed, under a great boom op named Guillermo Pena Tapia, himself a boom op who went union immediately after the film wrapped. I thought I knew how to boom, and Guillermo kicked my ass and disabused me of that notion to put it mildly! After almost every take he would shake his head and tell me he heard handling noise, or I was off axis, or missing lines. He really had to hold my hand through basic booming technique, and after the film wrapped I continued to grow as a boom op because I knew what I needed to work on and had developed the ears to hear correct booming! So from a purely technical standpoint, I am the soundie I am today because of his patience and instruction.
He taught me something even more important than booming technique though, which was a sense of my own limitations and humility. I thought I knew what I was doing when we first started working together, and I had an attitude about his criticisms because I thought he didn't know what he was talking about. But as the shoot progressed, I started listening, respecting what he was saying, and really trying. I started out arrogant and slow, and he kicked that right out of me! Taught me to hustle, to respect the hierarchy, and so so much more about narrative film sets. The last scene of the film was very tough for me, and involved I believe 5 actors and a dolly move. Needless to say I did NOT nail it and he told me after it was over that, FYI, that was a very easy scene to boom. Obviously that's pretty discouraging to hear, but I needed to hear it to know what to aspire to!
Fast forward, Guillermo hooked me up with my first low-low-budget feature, and got my started on the narrative path. When I got my first feature that actually let me bring on a (fairly green) boom op, I was able to direct him because of what I learned through my experiences being put through the wringer. A few years later, that boom op is absolutely killer, and always my first call. He has also told me multiple times that I am the pickiest/most exacting mixer he works with :-)
Sorry for the long story, but you really can't overstate how much a guiding hand helps out young guys and gals at the beginning of their careers! I never worked with Guillermo again, but I'm forever grateful for the ass kicking he delivered to me on that movie!