I love this as a research topic. Here are a few examples close to me. 1. The nature of variance in regression methods. The first time I heard about "soaking up

I love this as a research topic. Here are a few examples close to me. 1. The nature of variance in regression methods. The first time I heard about "soaking up the variance" in modifying stat models in brain imaging I had no idea what was going on. Then I spent a few years doing brain imaging and modified models to "soak up the variance" differently. Over the few years I came to grok the concept. I had a electrical engineering PhD colleague with an impressive resume who would argue with me about the effects of models. I realized that he knew the textbook stuff (which I didn't), but he didn't actually grok the concepts (which I did). 2. Once in an office was I mystified by hot spots and cold spots of wifi signal. One of my colleagues, a brilliant engineer, then explained to me what might affect the shape of the hot and cold spots, which is why he sits in certain places. I asked him if he had an intuition of how RF fields are distributed and he said yes, so I asked him how. He said, "I used to do a bit of tensor calculus".