For me, "best" is a relative concept. At the crux of the matter is "do". Whatever I do I don't internally or externally measure in terms of "best", as doing for me is not a competition within myself or anyone else. In fact, competition becomes a distraction that I strongly believe detracts from performance. I'll defer the matter of best to the critics, within and without.

Instead, for me it boils down to two factors: motivation and doing.

One motivator for me is curiosity, the pursuit of novelty and discovery, a luxurious motivator that would be my sole motivator if I were over the hump financially, but alas I am not.  So, my base motivator, avoiding starvation, pragmatically drives me to work for a living.  It's not a spiritually uplifting or intellectually fulfilling manner of existence that differentiates us from animals, but it ensures to sustain the physical vessels within which our spirits reside.  Perhaps, in a deeper sense, the motivation to avoid starvation is my only honest and pure one, and thus arguably the only one that ensures happiness.  Perhaps being wired with more abstract motivators opens a Pandora's box as these, such as "curiosity", or to be "better", or to be the "best", might poison pure happiness if not carefully understood what benefits they purport to derive.

The second factor, doing, is just the mechanics of fulfilling my curiosity.  If I'm curious enough, if the "voltage" of my curiosity is high enough, so to speak, the "current" will erupt in the form of doing.  Now, the doing could be difficult due to lack of resources or unwarranted and thus threatening to my employment, so it is important for me to find and harness those curiosities that lead to doings that benefit my employer in a timely fashion. Once the novelty wears off, I'm back to working to prevent starvation, completing obligatory work well enough to earn a paycheck and keep my job.

So, for me it is important to keep work interesting and in my spare time at work I explore ideas that are conducive to the employer's needs.  Let's face it, any job will become tedious for the same reason as the Coolidge effect regarding sex.  We're humans, not animals.  Our minds need stimulation, and repetition is not stimulating.  Is it any wonder we seek hobbies and amusements in our spare time away from the uncreative decades of monotonous work.  Only the few enjoy surviving from creative activities, like car designers, programmers, painters, marketers, business leaders, hunters, and so on. The vast majority will repeatedly assemble simple or complex widgets, over and over, with minor variations: whether cutting grass or troubleshooting a query's execution plan.

Perhaps my best is, philosophically, when I work to prevent my starvation and that of my family, after the higher motivators of novelty and discovery wither.  At that point, the job is like picking fruit from a tree, the fruit being the tasks and the tree being the company, for which I am grateful that they exist, that in fact somebody had once planted the seed and had grown and nurtured it to become the tree of industry that led to my employment.

These are my internal sticks and carrots, as Mr. Kubicek so adroitly alluded to.