Be Moderate

One has to consider the chance of a mischance. The impulses of the passions causeprudence to slip, and there is the risk of ruin. A moment of wrath or of pleasure carries you on farther than many hours of calm, and often a short diversion may put a whole life to shame. The cunning of others uses such moments of temptation to search the recesses of the mind: they use such thumbscrews as are wont to test the best caution. Moderation serves as a counterplot, especially in sudden emergencies. Much thought is needed to prevent a passion taking the bit in the teeth, and he is doubly wise who is wise on horseback. He who knows the danger may with care pursue his journey. Light as a word may appear to him who throws it out, it may import much to him that hears it and ponders on it.

Balthasar Gracian's Art of Worldly Wisdom
Aphorism # 207