Changing one's disposition

I for one do not understand why humans are the way we are. We act funny, we talk funny, sometimes we smell funny, or look funny... but most of all, we have these emotions that are impossible to explain. It's like you are standing there, perfectly happy and fine one moment, and the next it's like you've been hit by a semi. Sometimes it's just a mood swing from happy to sad, or the other way around. Sometimes it's just an unexplainable feeling... And sometimes it's that you thought you could live without someone until they show up one day. It's difficult to explain, but I'm sure you get the picture.
There's nothing worse than being completely over someone and the moment they are back, right in front of you, you realize you aren't. You realize you wish you still had something or wish they still wanted something with you. But you also realize you can't change anything. You can't make something happen. You can't, and although a part of you wants to, you know that you can't have it back.
Sometimes things hurt worse than others. Sometimes they are just a small pinprick, and other times it's like you've been stabbed in the stomach with a dagger. You can't explain it. Sometimes you don't even want to feel the way you do. Sometimes, you are just numb. Like I said, humans are funny critters. We just seem to march to the beat of a different drum.