Yeah, our oldest trained at 20 months with zero pushing from us. My wife was a stay-at-home mom and was nannying a friend's older daughter for a little extra money. Her friend's daughter was mostly potty trained, and that peer pressure ended up being all that was needed. We had it pretty easy. And then our youngest came along. He really wanted to use the potty like his big sister, but his was a case of being willing before he was physically ready. His bladder seemed to have the capacity of a shot glass, so he needed to go very regularly, and it was always urgent. (Road trips were quite miserable!) Still, I think we had it easy with him too, because he was very motivated by the idea that using the potty was what big kids and adults do. He was a lot like the ideal kid in the Pull-Ups ad who's playing, needs to go, and diligently runs off to the bathroom. He just...usually didn't get there in time. We were patient, and he ended up daytime-trained around age three.
In the end, I don't know whether we did something right or were mostly lucky. For both of our kids, seeing another kid use the potty seemed to have a big impact. I sometimes wonder, in cases where a child is very resistant to using the potty, if they've ever seen anybody else use one (or the toilet). Kids are born copy-cats, so modeling the behaviors you want is one of the best ways to get them!