Why do most secondary lovers like to put a smile on a sentence?

I didn't know much about this problem myself at first, but I gradually understood it after contact and use.

First of all, I remember that when I first entered the second circle, I saw many bosses chatting with themselves with smiles, and then I didn't quite understand. But there will be a kind feeling. Later, I followed the bosses like this. Later, after getting used to it for a while, I gradually understood. Because I think the expression on your face when you say this sentence represents your expression and feelings. Personally, I think this is a tone of my speech and a habit, that is, if you don't express this expression after a sentence, you will feel something is wrong. This sentence is not enough to express meaning. And after a long time, I will feel that this is a supplement to my tone of voice. It will make up for it to some extent. Not face-to-face communication. I think this lovely communication will increase the interest of chatting with each other.