Arthur Schopenhauer said this quote

Men are like children, in that, if you spoil them, they become naughty. Therefore it is well not to be too indulgent or charitable with anyone. You may take it as a general rule that you will not lose a friend by refusing him a loan, but that you are very likely to do so by granting it; and, for similar reasons, you will not readily alienate people by being somewhat proud and careless in your behavior; but if you are very kind and complaisant towards them, you will often make them arrogant and intolerable, and so a breach will ensue.