Question

Berel has just come back from a trip to America (he lives in Israel). He proudly shows
you his prize purchase – a mixer with all the attachments, bought at a bargain price!
You see that he was sold an old model at a non-bargain price. Should you make him wise?

Answer

In Tractate Kesubos (16b) we are informed that there is a difference of opinion between
Beis Hillel and Beis Shammai as to what one should say about a bride at her wedding. Beis
Shammai hold that one should praise her for the qualities she actually possesses –
and if they are few or insignificant, that is all one can say! Beis Hillel are of the
opinion that one should praise every bride for her beauty and abundance of good qualities.
Beis Hillel support their position with the following argument: If you see that someone
made a bad purchase, should you praise the purchase or tell him that he got a bad deal?
All agree that you should praise the purchase! (If so, why do Beis Shammai disagree in the
case of a bride? Tosafos explain that Beis Shammai objects to making a law obligating
everyone to say something which is not factually correct. If someone actually made a
"bad purchase" in his selection of a bride, they would agree that one should
praise his "purchase").

From this Gemoro we learn that if you see that a person has already made a bad purchase
which he can not undo, you should praise his purchase even if this means making
statements which are not factually accurate. Although it is generally forbidden to make
factually untrue statements, in a situation where telling the truth would cause
unnecessary pain or distress, this becomes the correct mode of conduct. (For details of
when one can annul a purchase, see "Overcharging and Underpaying" on this site.)
What will you gain by making this guy feel bad (and mad – at the guy who sold him
these goods)? He has no recourse according to the halochoh, so just make him happy!
However, if he has not yet made a purchase or he has a genuine opportunity to return the
goods, you should make him aware of the problem. Since he is thereby able to avoid a bad
deal, you are considered as if you returned his lost article (hashovas aveidah). By the
same token, even if he is unable to return the goods on this occasion, if he is likely to
make the same mistake in future unless he is warned, go ahead and tell him the truth about
his purchase. Temporary pain is better than heavy future loss (the motto of all dentists)!

THEREFORE, since Berel is unlikely to take the mixer back to America, just
praise his purchase and make him feel good. If you think he is likely to patronize the
same electrical supplier on his next trip, you should warn him. He may be upset now, but
in the long term he will be happy you made him aware of the problem. (Recommended reading
on this subject: Chapter 9 of Hilchos Rechilus in the Sefer Chofetz Chayim).