For example, a really friendly, funny person just seems to click with you and you thought that, "Wow, she's so cool!" and maybe you would be good friends in the future. However that future just does not come because she just doesn't think of you the way you think of her. Or when you had a falling out with your best friend and you miss your friend so much you thought that your best friend would just miss you as much. But then your so called 'best friend' think only of you occasionally (or make that 'when he/she is bored').
Why so? Is it because they have been paid too much attention by others? Is it because you are just too pathetic to be around with? Or is it because they just do not care anymore. So why, even with this points in mind, do you still think of them? Why do you still care? Why do we even need to care?
You know, even when you try so hard to forget it; spend most of your time with other people, caring more for another than the person in mind, throwing yourself into work, etc. etc. the person just sticks in your head like superglue. It is like a plague you can't get rid off. Sometimes it just makes you wanna crack open that skull of yours and just dig out whatever annoying lump there is. And sometimes, it just hurts to know that really, the other person just doesn't care anymore.