מַצְרֵף לַכֶּסֶף וְכוּר לַזָּהָב וְאִישׁ לְפִי מַהֲלָלוֹ
There are good people and bad people in the world. But no one considers himself on the side on the bad guys. Thieves, corrupt individuals and even the worst criminals in the world, believe that they are doing the right thing, and they justify their actions in a thousand different ways. The Gemara echoed this ethical and psychological phenomenon by saying 2000 years ago: kol derekh ish yashar be’enav “Everything an individual does is right in his own eyes. ”  But if everyone beliefs that she is the good one, how should we differentiate between the good guys and the bad guys?

Rabbi Shemuel Pinhasi, Shelita, author of an extraordinary commentary on Pirqe Abot, explains in his book (Vol. 1, p. 87) that King Solomon formulated a “personality test” in the pasuq of Proverbs 27:21 saying “Silver is tested in the crucible; gold, in the melting furnace; and a man is tested by his praise” . The crucible and the melting furnace serves to examine the purity and quality of precious metals: the more time or temperature the metal needs to melt, the better its quality, and viceversa. In a similar way, examining how much a person “praises” others, you can measure the quality of that person. Rabbi Pinhasi explains that “praising” refers to using a positive language, thinking and speaking positively of other people. Focusing on identifying and praising the virtues of our friends, relatives and peers rather than in identifying and criticizing their flaws. Who is a “good” person then? The one that is constantly focused on the good side of others, and somehow ignores their shortcomings. When someone does something wrong, a good person sees it as a mistake,  and judges the person with the benefit of the doubt (I must clarify that we are not referring here to crimes or extreme cases, but to everyday social situations). A bad individual, however, does not have the ability to “praise”. He or she can not see any positive side of the other, and is always focusing on people’s negatives side. These people are not able to identify virtue, even when they see it, and therefore cannot “praise” a virtuous act.

Rabbenu Yona said: “The Tsadiqim (the good people) always praise and exalt others, they are eager to find positive things in their peers. The wicked ones, on the other hand, try to look for the negative, criticize and humiliate others.”Thus, the ability or inability to “praise”, is the test of a good or a bad personality.
The Sages of the Gemara, who should be regarded as the pioneers of modern psychology, explained why some people tend to see the good in others while others only focus on the bad. They said it with just four Hebrew words: כל הפוסל במומו פוסל. “When someone has a flaw, he sees his or her flaw in others”. We project on our peers whatever we carry within us.  Imagine that I’m a selfish person, constantly looking for making an impression on people, and show off my wealth, and when I make a donation I do not think about the benefit that I am bringing to this good cause, but rather the benefit that this donation will bring to me in other people’s eyes. Now, when I see another person,  a complete stranger, making a donation, I will not be praising his good deed, rather, I will be inclined to think, and perhaps say, that all that person wants is to show off his wealth in front of others.  My own flaws, my selfishness, blocks me psychologically from conceiving that another person can act with altruism and disinterest.
Now, if I’m a generous guy and when I donate money I’m always looking to support a good cause, when I see someone else donating money for a good cause, I will surely think positively of that person, and I will “praise” him!     My good qualities are projected into other people’s intentions.
We can understand now better King Solomon’s personality: when a person has the ability to  identify and “praise” other people’s virtues, it is because there are good qualities and purity of thought within that person.  And vice versa.