Actually have explicit understanding of the matter, not just the "learn by watching" kind.

Oddly, I tend to get the exact same "that was so helpful!" response, despite generally having a knowledge base that is almost entirely "learn by watching" and "well, this works but I have no clue why". It seems to help that I'm very good at making this clear.

Obviously, this only works if I'm teaching someone who can get by on that level of understanding; teaching people to understand something better than I do is tricky ;)