How do you behave when you are in love?

In your life, in those moments when you realized you were in love how did you react initially and long term, how did you treat the person? Did you immediately want to tell the person? Did you feel overwhelmingly happy or euphoric? Did you try to fight the feeling, not wanting to give so much of yourself to another person? Have you ever been in love and not realized it right away? In your opinion, did you give too much of yourself to the person? Did the circumstances cause a major upheaval in your life? Did you have unrealistic expectations of them? How did things end up?