"Leave this world a little better than you found it"
Robert Baden-Powell, founder of the world Scouting movement, from his last message in 1941
Cicero, from his 44 BC de Senectute
Original latin: Serit arbores, quae alteri saeclo prosint
There have been many subsequent variations, most common of which is:
"Society grows great when old men plant trees whose shade they know they shall never sit in."
"We think of ourselves far too frequently as just individuals, separated from one another, whereas you are connected and what you do affects the whole World."
Archbishop Desmond Tutu, 2008, speaking about "Ubuntu" the South African Nguni Bantu term literally translated as "humanity".
Finally technology can help us be selfish and altruistic at the same time. Finally we can get credit for good behavior; we can add to our own bank account without taking from others. We are talking here about the Reputation Economy pioneered by eBay and popularized worldwide by Airbnb. Your good deeds invest in your tomorrow, while bad behavior diminishes your opportunities in the future. Even better, by "spending" your karma credits, you increase your bank balance!
Bottom line: leave the sailboat and crew better than you found them.