Love is an emotion the brain recognizes. Like pain, happiness, or fear. You physically feel the affects of love. How does the brain know to do that? If you scrape your knee once the brain will always associate that feeling you had the first time with it, but with the “symptoms” of love, the brain is triggered only by that compatible someone. You could kiss ten people in a row, but you won’t feel butterflies or fireworks until you kiss the one you love. How does the brain work like that?