Why do people love?

Today is Sunday. The college library opens at 1 p.m. I came about 15 minutes too early. So I was sitting in my car with the engine on to keep the cool air inside the car. While I was sitting there, I was thinking about a question: why do people fall in love?

Logically, there are three possibilities. One is that two people fall in love at the same time. Another one is that one loves the other so much while the other one does not feel a thing. The third one is that both do not love each other, but they stay the course for some purposes other than love.I think the above three logical cases are feasible and existing in the real world.

Let's think about the first case first. Two people met each other and fall in love at the same time. This happens very often in the real world. Many love stories are like that. This is normal. But I do not think it can be real for a long time since people are changing all the time. It's is very difficult for two people to change in the same way. So I think this kind of love is also short-lived or emotionally unstable.

The second case, two people met each other. One loves the other only in one direction. Logically this is very possible. But emotionally, is it feasible? If it is feasible, then the one who loves may have some kind of emotional problems. One can love reading or love mountains like that. How can a person continue to love another person without getting love in return? People love reading without expecting the books love back. This is the pre-condition. How can a person love someone with such a pre-condition? So I have to think this kind of love has to be short-lived or emotionally unstable.

The third case, two people met each other without love between them. But they stay together anyway since they have purposes other than love in their mind. I think this kind of love can be long-lasting and enduring.