But one is enough; some of the most famous scientists only got where they were because they had a specific advisor. Neither the teacher nor student would ever have accomplished half as much working alone.
I can tell you the exact moment, problem, response, and teacher - that changed my life forever. It was at that single moment that I understood mathematics. I wasn't suddenly good at it. No, I still pretty much sucked at math. But, I understood it was a language and it was descriptive.
Many years later, that same teacher would be there to help me celebrate defending my dissertation. I didn't actually march, I was already to busy by the time spring rolled around. He's an old man, now. I still stop in and we are still fast friends.
That one comment changed my life. There's a not insignificant chance that it has had a small impact on your life, assuming you've been impacted by modern traffic engineering, or in some pedestrian venues, or had some goods delivered. All that from a single comment that is entirely obvious, in retrospect.