What really is love? How do you know you're in love?

Is love that funny feeling you get when you see someone across the room? Or that breathless weak sensation that comes too soon?
Is it the stupid jokes and random ramblings? Or all the juvenile things?
Is it the stupid faces that make him scary and ugly, but so much more adorable? Or his smile…unforgettable?
Is it constantly thinking about him and trying not to daydream? Or finding not thinking of him harder than it seems?
Is it staring off in space recounting memories together? Or trying hard not to think of forever?
Is it fighting all day every day, but only in a playful way...Or thinking of a "mean" thing to say?
Is it engaging in a battle of wits? Or is it a feeling you try so hard to resist?
Is it suffering through what you hate—a passion of your date's?
Or is it everything he does for you, to make every tiny dream come true?
Is it passion of all good things? And ignoring all the ill pains?
Is it sacrificing to be together? Or sacrificing so much, trying not to smother?
 Is it caring only about his happiness? And totally forgetting everyone else?
Is it, maybe, having nothing else matter? And him not caring if you get sadder...
Is it A kiss? A touch? Or An "I love you so much"?
Is it just one of these things? Or is it, like I believe, all of these and more in between?