This too, will pass
Once a great Sultan called someone in his court and instructed him to craft a ring. The ring must have an inscription, a sentence, such that, whenever the Sultan would read it, it will bring him to reality. In times of prosperity, it will keep him humble; in times of despair it will keep him from sorrow and depression.
The person returned to him after a few days with a ring, which had inscribed on it :
"This too, will pass".
Surely, the moments we pass, the phases of life we go through, are all very temporary and short-lived. No matter how big the achievement, or how huge the failure, or how sad the recent events, this time, will indeed pass.
So in fact, there's nothing to be carried away with. No amount of success should ever make us proud and arrogant. Because it's just a matter of time till it goes away from our life. Similarly, no grief, no loss should ever be able to depress us and send us into dark, deep despair, as surely with time, long or short, this cloud will pass as well.
Neither success nor disaster lasts forever in this world. Everlasting joy or sorrow can come only in the Hereafter. So to quote from my favorite poem, "If you can meet with Triumph & Disaster, and treat those two imposters just the same...", only then you may become much more content with life.