Liking Someone
The instant happiness you get from seeing them. Your inner fan girl screams when you guys accidentally touch. The race of your heart when they start the conversation with you. The butterflies you get when they smile at you. The tossing and turning of emotions when you see them with someone else who has a better chance with them than you. The exciting feeling you get when they trust you with something. The Love and Hate feelings you have towards them for being them.
This is how I could tell when I’ve got it bad, for someone.