Have you ever liked someone so much who likes you too, or tells you they do anyway? It raises your self confidence to an all time high. So when they suddenly drop you and act like nothing ever happened, that self confidence drops to an extreme low and you have to work your way back to an acceptable place. It takes a long time to get back to a place where you feel good about yourself. But after 2 years of not seeing or speaking to them, it only takes 2 seconds of interaction to plummet all of your hard work back to nothing, as if it was done to you all over again.