Wit without humanity degenerates into bitterness. Learning without prudence into pedantry. - James Burgh

If a favour is asked of you, grant it if you can. If not, refuse it in such a manner as that one denial may be sufficient.

If a great person has omitted rewarding your services, do not talk of it; perhaps he may not yet have had an opportunity, for they have always on hand expectants innumerable, and the clamorous are too generally gratified before the deserving; besides, it is the way to draw his displeasure upon you, which can do you no good, but make bad worse. If the services you did were voluntary, you ought not to expect any return, because you made a present of them unasked; and a free gift is not to be turned into a loan, to draw the person you have served into debt. If you have served a great person merely with a view to self-interest, perhaps he is aware of that, and rewards you accordingly: nor can you justly complain: he owes you nothing; it was not him you meant to serve.

If you would have a right to account of things from illiterate people, let them tell their story in their own way; if you put them upon talking according to logical rules, you will confound them.