Why we should have control over our minds
Let us first answer the inverse question, why we should not attempt to have control over our minds. There are a few good arguments here, many of them stem from the core of 'nature' ie, we should let our body and mind be in their natural state, we evolved to deal with reality very well so we should just let our nature guide us through and we would be the most complete, comfortable and satisfied. This is all very logical and even correct, but only when accepting an assumption that is very incorrect at it's core, that the world we evolved to deal with is the same world we built for ourselves now.
A Beautiful Machine for an Ugly World
We are indeed a beautifully intricate machine that is very efficient at going through the world, surviving, building, laughing and expanding. As mentioned earlier though, the world we have now is extremely different from the world our bodies and brains know what to do with, making our lives infinitely more difficult and complicated, because at it's core, acting against our nature, which is what we seemingly have to do to exist in this world, is an uphill battle with constant struggle.
It is in your hands
An antidote to this chaos is creating a loose structure, an interpreter, a membrane between us and the world that puts us in a position to act in accordance to our nature and still have an active part in life. Find out what your nature needs, and find ways to bridge those needs with your goals, your games and your part in society. Ask yourself then: how do I use technology in a way that doesn't trample my nature? How do I work in a modern structured job without suffering the contrast from my most basic evolution? How do I manage my nutrition and intake when I can have whatever I want, whenever I want? (and am not built to handle said whatever). Answering those questions, and going about enacting those answers is the reason we as the modern human in the modern world, should have control over our minds.
sidenote: if you choose to "run away into the forest" you'll find you don't have to solve those sorts of problems