What should I do if I see someone I like talking and laughing with others?

It is normal for you to see someone you like talking and laughing and fighting with others, and you are very upset, unhappy and particularly uncomfortable. Because in the process of liking him, you have regarded him as your favorite object, so you will feel particularly sad when he maintains a better relationship with others than ordinary people. That's because you can't accept that someone has a better relationship with him than you do. So I think you should face up to your feelings. Since you like him, you should feel that this person is happy and you are happy. Don't feel uncomfortable just because he is happy with others. That kind of behavior is very selfish.