Great idea for a thread! I am sure I can think of lots given time, but a couple I recall straight away:
She was a devout catholic but as teenagers, when we were on our way out to a party, she would always say: "Be good - but if you can't be good, be careful!"
.. and her wise words on road safety: "He was right, dead right, as he went along, but just as dead as if he were wrong!"