In my opinion one of the most amusing parts of this game is the way you build your character to have a personality. Let me explain. This is a video game and your character litteraly has no emotion except for what is programed into it. You cannot sense things like smell, taste or have any built in intuition at all. It's all in 2D with no other real life emotions. Perhaps games in the future could advance in this area, but for now we must all deal.
Here is another way to look at it. Lets say you are an alien visiting from another planet and while you do indeed have a very wide range of emotion, it's not only on a different frequency than the residents of the planet you are visiting, it's a completely different way of communicating.
Your native language has a variation of telepathy, clairvoyance and premonitions. I believe the expression for such a thing would be called a sixth sense or ESP. Those around you have the ability to read emotions, but unbeknownst to them, since you only look like you are from earth, your communication skills are completely different, they misunderstand your intentions, wants and desires. Ok, that analogy might be way over the top but it's all relative.
As you advance your friendship, villagers will approach you and tell you they have something to teach you. It's called a reaction. They explain what it means and how to act it out in a particular situation so you can communicate with the others around you. After all, you are living with a bunch of talking animals. This theory makes perfect sense.
Once you learn the reaction you can find the option by pressing the "ZR" button on your Switch. A favorites menu will appear. If you press the "Y" button you can see a full list. Press "A" to choose your reaction. It is a good idea to program your favorites menu for a faster response time, as the villager will often walk away before you can use your alien communication skills to come up with something to say back in the particular situation. You can edit your favorites menu to include those you think you will get the most use out of, also making perfect sense when applied to real life, as we all tend to use the same group of reactions and facial expressions to a given situation. This is called a personality and your character evolves their communication skills based on their experiences just like in the real world.
It makes me wonder if this is a clue that they are subconsciously preparing for the future of AI games. The characters inside the game would actually have real emotions. But in order to do that the player would have to have an implanted device inside them. Unless there is a technology that I am not aware of. Like your entire brain was an infestation of nanites controlling your every move by a learned algorithm. The future of gaming is going to be an interesting one.
Now imagine of you could implant that type of play into an AI robot. It would be like creating your own Data from Star Trek. And you thought this was just your average cozy sim.