Baby Names Beginning With "W": Meaning: Plain?

Questions

"The hardest thing to understand in the world is the ."- Albert Einstein (1875-1955)?

"If we want things to stay as they are, things will have to ---------."- Guiseppe di Lampedusa (1896 - 1957)?

"If ------------ didn't exist, all the money in the world would have no meaning."- Aristotle Onassis (1906-1975)?

"If you always do what interests you, then at least one person is -----------."- Katharine Hepburn?

"If you are patient in one moment of anger, you will avoid -------------------- of sorrow."- Chinese Proverb?