People give flowers as presents because flowers contain the true meaning of love. Anyone tries to possess a flower will have to watch its beauty fading. But if you simply look at a flower on a field, you will keep it forever, because the flower is part of the evening and the sunset and the smell of damp earth and the clouds on the horizon.
I'll be honest with you here... I'd describe it as a wild, almost uncontrollable need to be a part of that person's life. A passion, really. Yes - in fact, the best way of describing it is if you lost everything - your job, your home, your car - but that person was still by your side, none of it would really matter.