That silly, giddy phase in a relationship. That phase which the two of you spend all night talking even though you know you'll both feel horrible tomorrow because, well, you don't feel tired now. It's the phase where every time the other person is mentioned in conversation, you smile or blush. When you walk around with a dopey grin on your face for no reason. The phase where you might notice the flaws of the other, but they don't make one spot of difference.
The phase which, according to scientists, never lasts.
Scientists have a word for everything, don't they?