Who said "You should be grateful for every person you meet."?

This quote is attributed to Luffy.

You should be grateful for every person you meet. - Luffy

"You should be grateful for every person you meet."

Luffy Gratitude

"I'm gonna be King of the Pirates!"

"A man's dream will never die!"

"I don't care what happens to me, I'm gonna help my friend!"

"Being alone is better than being with the wrong people."

"Gratitude makes life richer."

"A grateful heart is a happy heart."

"Respect those who came before us."

"Life's greatest treasures are the people we love"