"If ya can't do good; don't do at all" - My Friend
Be respectful to your superiors, if you have any.
Mark Twain
You ought never to "sass" old people- unless they "sass" you first.
Mark Twain
We despise all reverences and all the objects of reverence which are outside the pale of our own list of sacred things. And yet, with strange inconsistency, we are shocked when other people despise and defile the things which are holy to us.
Mark Twain
From the time a woman is seven years old till she dies of old age, she is ready for action, and competent. As competent as the candlestick to receive the candle. But man is only briefly competent:...After fifty his performance is of poor quality; the intervals between are wide, and its satisfactions of no great quality to either party; whereas his great-grandmother is as good as new.
Mark Twain
and here's a funny(er) one:
If a person offends you, and you are in doubt as to whether it was intentional or not, do not resort to extreme measure; simply watch your chance and hit him with a brick. That will be sufficient. If you shall find that he had not intended any offense, come out frankly and confess yourself in the wrong when you struck him; acknowledge it like a man, and say you didn't mean to.
Mark Twain