JB, there is a difference between what people are aware of and what they can articulate. Usually when they think a shoe looks wack, it is the proportions of things they are responding to.
I’m always trying to think about it. Lets say I want to do a sleek trainer. Sleek compared to what? A hiking boot? A cross trainer, a fashion slip on? It helps to know what the norms are (in everything, not just proportion) so you can push beyond them in a way that makes sense to the consumer and aligns with your goals for the project. Otherwise its just another drawing of a shoe. You can get by on that for a little while but eventually you fall into a predictable pattern yourself without realizing it.
The way I try to do it at least.