Most people confuse selfish goodness, with selfless goodness.
The heart is a reactive machine, hence it cannot decipher between truth.
The famous story is told about three great sages in ancient Israel discussing Roman construction in Israel; One praised their bathhouses aqueducts etc. (which are still visible,) the second was silent not wanting to offend Rome, and the third, the great and holy Rabbi Shimon Bar Yochai (Author of the Zohar, the primary text of Kabbalah) said “They build bathhouses so they can bath themselves and they build brides to collect taxes etc.”
In other words, the first sage was under the false impression that what feels good to the heart is altruistically made, while Rabbi Shimon Bar Yochai was able to decipher where the Romans true heart lies, namely in self gratification which in retrospect and 20/20 hindsight we all know Rome didn’t conquer to help the less fortunate, but the other way around.
So how do we overcome our hearts stupidity? How can we decipher right and wrong, altruistic and selfish, goodness and in fact evil motivations?
The answer is that we cant; however each and everyone of us must arrive at the level were we feel no dependence on fellow man for we know that fellow man is only – to borrow a mystical term – like a hammer in the hand of the builder, a tool used by G-d to bestow his love or his rebuke upon us.