You should not praise an act of apparent generosity unless you believe it is actually performed out of selfless motives, and you should not condemn an act of apparent selfishness unless you believe it is actually performed out of self-centered motives
Daniel was right not to praise Margaret for offering to share her house with a visiting French family, since he believed that she made the offer only because she hoped it would be reciprocated by an invitation to use the family's apartment in Paris.