What does it mean to be "original"? Two things: 1. Something serving as a model or basis for imitations or copies. 2. An eccentric or unusual person. That doesn't seem so bad, right? However, when society is telling someone to "be original", it is simply saying the exact opposite. When society says "be original" it means to be just like every other human being on this planet -- but not too similar or risk being called "fake" -- or be considered "weird". It has, in fact, been stated that every single idea has already or previously been thought up by another person(s) in the world.
"There is no such thing as a new idea. It is impossible. We simply take a lot of old ideas and put them into a sort of mental kaleidoscope. We give them a turn and they make new and curious combinations. We keep on turning and making new combinations indefinitely; but they are the same old pieces of colored glass that have been in use through all the ages." -Mark Twain
So, no, you can't tell someone to "be original", because from this time forward, original thoughts are nowhere to be found. In the first definition of "original" (serving as a model or basis for imitations or copies), it is clear what society is trying to do. It preaches to "be original", but only if your originality is the norm of the population. "Don't become fat, but always be original." "Don't become anorexic, but don't forget to be original." "Don't be an outstanding scholar, because that means you're fake." "Don't fail your classes, because that, too, is fake."
NOTHING WILL EVER BE ORIGINAL AGAIN. At least not if you are going by what society thinks. However, if you go by the second definition, there is still a chance for originality to exist.
So, what I'm saying, is to be yourself. Society will throw a fit, but if everyone were themselves, would the high standards of society even be a thing anymore? Eat whatever you want, say whatever you want, and dress however you want. BE. YOU. There isn't a better time to be the person you were meant to be than now. Nobody can be you for you, so you might as well grasp it and be you yourself.
Dr. Seuss said it well when he said: "Why fit in when you were born to stand out", and "Today you are you! That is truer than true! There is no one alive that is you-er than you!".