My Inventions - Nikola Tesla - Bog

The progressive development of man is vitally dependent on
invention. It is the most important product of his creative brain. Its
ultimate purpose is the complete mastery of mind over the material
world, the harnessing of the forces of nature to human needs. This
is the difficult task of the inventor who is often misunderstood and
unrewarded. But he finds ample compensation in the pleasing
exercises of his powers and in the knowledge of being one of that
exceptionally privileged class without whom the race would have
long ago perished in the bitter struggle against pitiless elements.

Speaking for myself, I have already had more than my full measure
of this exquisite enjoyment, so much that for many years my life was
little short of continuous rapture. I am credited with being one of
the hardest workers and perhaps I am, if thought is the equivalent
of labor, for I have devoted to it almost all of my waking hours. But
if work is interpreted to be a definite performance in a specified
time according to a rigid rule, then I may be the worst of idlers.
Every effort under compulsion demands a sacrifice of life-energy. I
never paid such a price. On the contrary, I have thrived on my
thoughts.