Here are quotes I love:

“If you have fear of some pain or suffering, you should examine whether there is anything you can do about it. If you can, there is no need to worry about it; if you cannot do anything, then there is also no need to worry.”- Dalai Lama

Similar by Dalai Lama

“If there is no solution to the problem then don't waste time worrying about it. If there is a solution to the problem then don't waste time worrying about it.”

"Don't cry because it's over. Smile because it happened."
Dr. Seuss

"Most folks are as happy as they make up their minds to be."
Abraham Lincoln

"It is during our darkest moments that we must focus to see the light."
Aristotle Onassis

"Holding on to anger is like grasping a hot coal with the intent of throwing it at someone else; you are the one who gets burned."
Buddha

"The weak can never forgive. Forgiveness is the attribute of the strong."
Mahatma Gandhi