Palestinian boys play next to Israel's controversial barrier in 2004 in the neighborhood of Abu Dis in the West Bank. Here are quotes to help you smile like these kids on International Happiness Day. Getty Images

Sunday is International Day of Happiness, a global celebration of contentment adopted by all 193 members of the United Nations. The event is in its third year and aims to — of course — help people create happier lives for themselves and others. Organizers say positivity should be a priority for everyone.

"A profound shift in attitudes is underway all over the world," the holiday's official website reads. "People are now recognizing that 'progress' should be about increasing human happiness and well-being, not just growing the economy."

Whatever gets you smiling — a boyfriend, a puppy, your favorite food or a nice breeze — be sure to take some time Sunday to indulge. While you're grinning, share these famous sayings to spread the good feelings.

Here are 20 quotes about happiness, collected from GoodReads, BrainyQuote and PostivityBlog:

“For every minute you are angry you lose 60 seconds of happiness.” ― Ralph Waldo Emerson

“There is some good in this world, and it's worth fighting for.” ― J.R.R. Tolkien

"It is neither wealth nor splendor but tranquility and occupation which give you happiness." — Thomas Jefferson

"It’s a helluva start, being able to recognize what makes you happy.” — Lucille Ball

“When one door of happiness closes, another opens, but often we look so long at the closed door that we do not see the one that has been opened for us.” — Helen Keller

“Folks are usually about as happy as they make their minds up to be.” ― Abraham Lincoln

“It takes no more time to see the good side of life than to see the bad.” ― Jimmy Buffett

“With mirth and laughter let old wrinkles come.” ― William Shakespeare

“The only joy in the world is to begin.” — Cesare Pavese

“We are all in the gutter, but some of us are looking at the stars.” ― Oscar Wilde

“Count your age by friends, not years. Count your life by smiles, not tears.” ― John Lennon

“If you spend your whole life waiting for the storm, you’ll never enjoy the sunshine.” — Morris West

“If you're reading this ... Congratulations, you're alive. If that's not something to smile about, then I don't know what is.” ― Chad Sugg

“You can't be happy unless you're unhappy sometimes.” ― Lauren Oliver

“Happiness is not in the mere possession of money; it lies in the joy of achievement, in the thrill of creative effort.” — Franklin D. Roosevelt

"Don't wait around for other people to be happy for you. Any happiness you get you've got to make yourself." — Alice Walker

“A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty.” ― Winston Churchill

“We're all golden sunflowers inside.” ― Allen Ginsberg

“If you smile when you are alone, then you really mean it.” ― Andy Rooney

“It isn’t what you have, or who you are, or where you are, or what you are doing that makes you happy or unhappy. It is what you think about.” — Dale Carnegie