"All things must pass"
A George Harrison song and album but also the Buddha’s final words: “All things must pass away. Strive for your own salvation with diligence.”
It is a reminder that nothing is permanent. What we perceive as “good” and “bad” are both temporary. A bad mood will eventually pass. Your gold fish will eventually die. And so it is a good reminder, not to take things too seriously since they too will go away.
For more info: http://www.artofdharma.org/buddhas-last-words-all-things-must-pass/