Mark Twain

about his life:
http://en.wikipedia.org/wiki/Mark_Twain

and some quotes that caught my eye:

Always do right. This will gratify some people and astonish the rest

Honesty is the best policy - when there is money in it.

If you tell the truth you don't have to remember anything.

Keep away from people who try to belittle your ambitions. Small people always do that, but the really great make you feel that you, too, can become great.

The worst loneliness is not to be comfortable with yourself.

A lie can travel halfway around the world while the truth is putting on its shoes.

For more: http://www.quotationspage.com/quotes/Mark_Twain/1

One I just found in German:
"Sei artig und du wirst einsam sein"

;-)

I could comment on each of this quote, but I won't! This shall be for you, reader to think beyond daily thoughts, trying to catch a deeper, philisophical level of spirit and interaction between humans!