What is this thing for tidyness? It's so much easier to find something if it's right in the middle of your floor, than if it's tucked away somewhere. Cleaning or tidying your room is a boring chore. Probably because you know that by tommorow it will look like an earthquake's hit it.
Your room is your haven, and if messiness is part of you, it should be shown in your room too! Messiness is a form of expression, not laziness. But being lazy isn't wrong. Most people are lazy sometimes, and if they are, they're probably lazy about tidying up their room (or house) Some people are lazier than others. Teenagers are lazy because they have better things to do than tidy, tidy, tidy.
Is this some mother/neat thing? Why are mothers (or fathers) obsessed with keeping rooms "neat"? It's not like your mom has to spend any time in your room. She doesn't sleep in it. work in it, relax in it, you have to. Rooms are just so "impersonal" if they don't have that possesion touch. (Like, possesions all over the floor)
Face it, your room is for your benefit, it's part of you, and you probably love having a room. If you have to share, it's bound to be even messier, but you can always blame the mess on your sibling!
Keeping clothes of the floor is practical, because you might want to wear them again and they won't look or feel too great if they're all creased, bitty and stained. But magazines, paers, books, and whatever else is a personal addition. It expresses and describes the things that you are fond of, and leaves them on show for others to enjoy.
We're not just talking about your room, though. Leaving a mess anywhere else is a sign that you've been there and left your mark. It might be rude if it's someone else's house, but people can clean it up.
In the end, messiness is a personality trait. You can't help it, and you shouldn't try to change it.