Mental models are a bit like windows in a house. If you look outside from one window, your view is different from another. As product designers, we get to build the windows, and the customers get the view! The good news is that it’s incredibly easy to build windows on Day 1 – the customer’s view is unobstructed. On Day 2, the customer is already used to the window and the view. To change it, you’d need to build a new mental model for them. It’s possible, but it’s much harder than on Day 1. In other words, build the right mental model from the beginning, and you’ll be a model of success.