Because we have a tendency to long for a mate. We all (for the most part) naturally want someone to spend the rest of our lives with....and have a family. It’s wired in our brains. We see someone and think of them as the perfect mate. There’s also the fact that people get jealous when they see two lovers, so that’s why literal first graders have a crush. Plus they want to fit in.
The feeling of love also releases dopamine, a happy feeling in our brain. The thought of someone caring about you warms your heart, right? It makes you feel safe. Once you see the “perfect” person, your stuck on that thought, and that develops the want to have them as your partner- also known as a crush. The feeling of staying with them forever because of the traits you like about them gives you the crush. You long to be with them. Again, the dopamine is a good feeling, so people do those things like obsessing over that single person you love. It makes them happy to think about them. Hope this helps! Sorry it’s long haha.
