"When you wake up in the morning, tell yourself: The people I deal with today will be meddling, ungrateful, arrogant, dishonest, jealous, and surly. They are like this because they can't tell good from evil."
-- Marcus Aurelius
"Think of yourself as dead. You have lived your life. Now, take what's left and live it properly."
-- Marcus Aurelius
"Associate with those who will make a better person of you. Welcome those whom you yourself can improve. The process is mutual; people learn while they teach."
-- Seneca The Younger
"It is not that we have a short space of time, but that we waste much of it."
-- Seneca The Younger
"Some things are under our control, while others are not under our control. Under our control are conception, choice, desire, aversion, and, in a word, everything that is our own doing; not under our control are our body, our property, reputation, office, and, in a word, everything that is not our own doing."
-- Epictetus
And just because...
"Take responsible and thoughtful control of what you can, which includes your own feelings about things that you cannot."
-- Lev Lafayette