Any mathematician will tell you that mathematical proof is one of the most beautiful phenomenon on earth. Hence, it is also one of the most creative endeavours known to man.
To those whom right now are reminded of gut-wrenching high-school math classes, please hear me out for 4 paragraphs.
A Definition of Beauty
Proofs are beautiful because they seem to be built from random, disparate chunks of information. We make assumptions, and then make assertions based on those assumptions, and then make more assumptions.
And yet, when we're done, what is before us stands not just robust in face of mathematical checks, but also stunningly elegant to the untrained eye. (or rather, the semi-trained eye)
Like the northern lights, or even a simple sunset, we find beauty in the fact that 3 trillion simultaneous, seemingly random interactions give rise to something that just looks amazing.
And finally, just like a beautiful sunset, proofs lay before us an infinite complexity, one that gets ever more beautiful the more we look at it. And that is why mathematicians do what they do: their reward is a close-up view of an eternal sunset.