[tem-per-uhns, tem-pruhns]

–noun

1.moderation or self-restraint in action, statement, etc.; self-control.

2. habitual moderation in the indulgence of a natural appetite or passion,

Also,

to temper:

to produce internal stresses in order to impart strength or toughness to or to tune as one would an instrument.
There is no denying that there can be certain advantages to extremity: to become profoundly skilled in a very specialized pursuit it can be immensely helpful to have extreme focus while obtaining information, practicing, and applying that practice and information in reality.  However, in most cases, we are best served by taking a measured and moderate approach.
This can be difficult to do, for a whole host of reasons. We are creatures wired to seek pleasure and avoid pain. It can be exciting to fling oneself, figuratively or literally, off a precipice to fall. It can also lead to terror and pain. Everything at its price. We wend toward the perimeter without even realizing we are on our way; to feel things at the utter extent of our capacity, we are fully activated. We are sure we are alive, and at these moments, we are giddy with it.
And there is no question that to run to the far end of ourselves tells us about who we are, what is really important, where we are more flexible than we thought, and where we will break. It is profoundly satisfying to know these truths about oneself. To be reassured and surprised by what we discover in the crucible, and as we rise from it.
But to take a middle course is a challenge of a different sort. To strike a balance between excitement and security, acquisition and retention, pleasure and progress,  such that our needs for both novelty and predictability are met. It is not always easy to reign in the headlong zeal toward something that inspires us to passion. It is far easier to simply allow the current of feeling wash over and carry all sense away.  To instead attempt to predict the pull and the eddy, to submerge but a little; to feel what is happening, but try to steer what course you will might not deny all the advantages of immersion, but allows for greater navigability. Less chance to run aground, to strike the rocks, to sink.