Then the question is, why are single people all dogs? Can't you order a single cat? Isn't it cute, too Cats and dogs are the most pets kept by human beings, so it is very angry to choose cats over dogs!
But "single dog" is a self-deprecating word, and this species modified by "single" needs at least two conditions:
First: this species needs to show emotion or close relationship with people. The ridicule of "single" and "dog" forced a bit of sadness. Users of this word put themselves at the bottom of eighteen layers of hell or sewer to mobilize the weak effect and quickly find group identity and emotional resonance. Therefore, an animal that makes a single lament needs an animal with a strong personality to bear it. As a friend of human beings, dogs are the earliest domesticated animals. There is also a proverb-dogs can do three thousand, and cats can do eight hundred. Cats are treacherous courtiers and dogs are loyal courtiers. It shows that in the eyes of many people in China, dogs are honest, even cowardly, easy to suffer losses, and they are animals with great feelings for human beings. Sticking a dog's label on your head is more emotional than claiming to be single!
Second: As I said before, the word "single dog" comes from black, so this word needs to have a certain "insulting" meaning. In the cultural context of China, saying that a person is a dog is mostly demeaning and insulting. The most famous line is like a well-known classic line in A Chinese Odyssey-you see that man is like a dog.
To sum up, the origin of the word "single dog" is actually a name that conforms to national conditions, respects tradition and contains culture. It contains the sadness and helplessness of the majority of single people. When it is dark, I laugh and cry. Alas ... I accidentally recalled the sad past of Shenmajun.