Getting cash out of an ATM is a very familar process. The goal state is to get your cash. In Argentina the cash comes out before the card, the goal state comes before the end of the process. We build mental models and apply them in new situations - apply past experience to current situation.
Improving cruise buying process, started with user research including with phone channel which was making much more sales than the website. Mapped questions to each stage of the buying process, this turned out to be a mess on the website so people were dropping out to the telephone channel. Sorted out the information architecture and the process improved.
People don't like to think. If people don't have to think then the process is easier. Match the mental model (get inside people's heads) and give them the information they want.
Beauty evokes emotion. Beautiful things are easier to use. Positive emotions release dopamine. Evoke emotion (negative emotion also works).
Subconscious controls instinctual, base, emotions - fear, sex, hunger &c. Next to area of brain that deals with faces (fusiform gyrus). Food, faces, other strong base stimuli.
If a mental model doesn't exist then research can help build one.
There is academic research into psychology, find papers that are related to elements of design such as facial recognition.