I do an occasional pilgrimage to my old high school math teacher. He's in his 80s now, but in his last year before retiring, we won a math contest for European

I do an occasional pilgrimage to my old high school math teacher. He's in his 80s now, but in his last year before retiring, we won a math contest for European International schools. He was very happy about that. The guy still gets visits from people in their 60s that he taught decades before me. He really made the subject come to life, had a sense of humor, and was generally a good guy. He also ran the school math teams. Several kids in the years above me did quite well on those, all down to him giving us accelerated content and questions that were "actually interesting" rather than dozens of the same thing over and over. Of course it varies what that means depending on where you are in your journey, but at each step there tends to be an aha! moment where things come together. I caught up with him a few weeks ago, and he told me he actually didn't enjoy the university level of mathematics. Somehow things got very dry and boring, and that's part of why he ended up teaching high school.