Anger management
It is 1 letter short of DANGER. Hence, it is wise to control your ANGER than to let it control you.
For our Kan Tang folks,
脾气 pí qì = temper
本性 běn xìng = instincts
本事 běn shì = ability or skill
So, a simplified translation of the above message will be:
To allow one's temper to rise takes only instincts
To allow one's temper to cool down requires skills