Openmindedness

There can be few traits more costly than a closed mind. It can't see all the chances passing by - nor guess their worth. This subjects one to potentially unlimited opportunity cost. Consequently, few other flaws could be of higher priority to fix.

Emotional Courage

Sensitivity doesn't indicate weakness; hiding from your feelings does. Emotional Courage is the willingness to confront whatever difficult feelings you're avoiding - and is one of the preeminent qualities of the modern hero.

Humility

If there's one thing that life has repeatedly drilled into my head: it's that none of us are as great as we think. But the ego avoids being humbled so fiercely - as if it were death itself - even though it should be seen as a gift. Being humbled doesn't have to feel embarrassing, it could be enjoyed, and to react that way would incentivize more growth.

Optimism/Resilience

There are few limits to how horrible life can become, and no boundaries people will not exploit. Most of us are born into an uphill battle that only a fool could be hopeful about. And yet, if you are optimistic anyways, even against seemingly impossible odds, then no one can ever crush your spirit, or know for certain what lucky anomalies may lay ahead.