I'm not gonna paraphrase this because I am lazy, but here is the whole quote about social media likes: " According to an article by Harvard University researcher Trevor Haynes, when you get a social media notification, your brain sends a chemical messenger called dopamine along a reward pathway, which makes you feel good. Dopamine is associated with food, exercise, love, sex, gambling, drugs … and now, social media. Variable reward schedules up the ante; psychologist B.F. Skinner first described this in the 1930s. When rewards are delivered randomly (as with a slot machine or a positive interaction on social media), and checking for the reward is easy, the dopamine-triggering behavior becomes a habit." The article may be found at: https://now.northropgrumman.com/this-is-your-brain-on-instagram-effects-of-social-media-on-the-brain/

Basically, every time time we get a social media like, we get a burst of dopamine which makes us feel good and who doesn't like to feel good?