No blessing lasts forever.
Unexpected results are the rule rather than the exception.
If you say hard things you must expect to hear them in return.
There are games in which it is better to lose than win.
What you lend is lost; when you ask for it back, you may find a friend made an enemy by your kindness. If you begin to press him further, you have the choice of two things - either to lose your loan or lose your friend.
Laws are subordinate to custom.