If you lack critical thinking (i.e. if you don't think) while reading Nietzsche, you will not understand a thing. You will falsify and misinterpret his message and will make yourself stupid. His works take time to decipher. True understanding in general takes time; good reading is good rumination. You must have time to understand, contemplate and draw and connect all the consequences. Not to mention the desire, which is the most important thing a thinker needs. The desire to understand is fundamental here. But let's hear what Nietzsche has to say about ADHD monkeys having learned to read:
The worst readers.— The worst readers are those who proceed like plundering soldiers: they pick up a few things they can use, soil and confuse the rest, and blaspheme the whole.
I am 100% sure no one bothered reading those Schopenhauer essays I linked earlier, so, of course, I'll link some more and post some quotes, so we can easily see what the man has to say about reading, without the need to expend any energy clicking any links and without reading too many paragraphs in a row and draining our precious eyes too much:
Reading and learning are things that anyone can do of his own free will; but not so thinking. Thinking must be kindled, like a fire by a draught; it must be sustained by some interest in the matter in hand. This interest may be of purely objective kind, or merely subjective. The latter comes into play only in things that concern us personally. Objective interest is confined to heads that think by nature; to whom thinking is as natural as breathing; and they are very rare. This is why most men of learning show so little of it.
It is incredible what a different effect is produced upon the mind by thinking for oneself, as compared with reading. It carries on and intensifies that original difference in the nature of two minds which leads the one to think and the other to read. What I mean is that reading forces alien thoughts upon the mind — thoughts which are as foreign to the drift and temper in which it may be for the moment, as the seal is to the wax on which it stamps its imprint. The mind is thus entirely under compulsion from without; it is driven to think this or that, though for the moment it may not have the slightest impulse or inclination to do so.
But when a man thinks for himself, he follows the impulse of his own mind, which is determined for him at the time, either by his environment or some particular recollection. The visible world of a man’s surroundings does not, as reading does, impress a single definite thought upon his mind, but merely gives the matter and occasion which lead him to think what is appropriate to his nature and present temper. So it is, that much reading deprives the mind of all elasticity; it is like keeping a spring continually under pressure. The safest way of having no thoughts of one’s own is to take up a book every moment one has nothing else to do. It is this practice which explains why erudition makes most men more stupid and silly than they are by nature, and prevents their writings obtaining any measure of success. They remain, in Pope’s words:
For ever reading, never to be read!
http://ebooks.adelaide.edu.au/s/schopenhauer/arthur/lit/chapter4.html
And:
Students, and learned persons of all sorts and every age, aim as a rule at acquiring information rather than insight. They pique themselves upon knowing about everything — stones, plants, battles, experiments, and all the books in existence. It never occurs to them that information is only a means of insight, and in itself of little or no value; that it is his way of thinking that makes a man a philosopher. When I hear of these portents of learning and their imposing erudition, I sometimes say to myself: Ah, how little they must have had to think about, to have been able to read so much! And when I actually find it reported of the elder Pliny that he was continually reading or being read to, at table, on a journey, or in his bath, the question forces itself upon my mind, whether the man was so very lacking in thought of his own that he had to have alien thought incessantly instilled into him; as though he were a consumptive patient taking jellies to keep himself alive. And neither his undiscerning credulity nor his inexpressibly repulsive and barely intelligible style — which seems like of a man taking notes, and very economical of paper — is of a kind to give me a high opinion of his power of independent thought.
http://ebooks.adelaide.edu.au/s/schopenhauer/arthur/lit/chapter4.html
So all the greatest genius of mankind are saying the same thing: spending all your days reading is a sure way to make yourself a braindead imbecile. Schopenhauer, Nietzsche and me: we are all saying you are better off leaving your room and trying to actually accomplish something. When the time comes for you to think, you will think. No need to force any of this.
At the end of the day, and to come full circle on this, writing merely simulates thoughts. When you read something you are only ever getting a glimpse of what the author thought. It's always up to you to USE your brain to extract (i.e. to create) the meaning of the text, by "placing yourself" in the author's feet and trying to recreate (by using the words and their relationships) what he SAW, what he FELT. For only THAT is real. The text itself is meaningless: the words by themselves signify nothing as Derrida showed time and again. You can take any word you want from the dictionary and make it mean anything. You can even make this very post of mine mean THE EXACT OPPOSITE of what I'm trying to explain. But anyway: writing is SIMULATION, it is not REALITY. The reality are the THOUGHTS — and some thoughts are not accessible to everyone — no matter how much you read, if you lack a complex, powerful, sensitive (all these terms are interchangeable here) brain enough to think these thoughts — to FEEL these thoughts — you will forever misinterpret the author. The higher the thoughts, the higher the being: you must first of all place yourself high enough to earn the RIGHT to these thoughts. To be able to SEE these thoughts. Understanding goes from higher to lower as God himself told us. Can we teach an ape how to read? Perhaps we can... but good luck teaching him quantum mechanics!
In fucking summa: reading alone does not a genius make. You need a powerful enough brain and the necessary EXPERIENCES for that. Further: the brain and the experiences are inextricably related: for the experiences SHAPE the brain, and it's the brain ITSELF that experiences.