They (the Israelites) could not drink the waters of Marah because they were bitter (Exodus 15:23). The assumption is that it
was the water that was bitter.
The Baal Shem Tov said, The antecedent of the second pronoun they is the Israelites, not the waters. It
was not the water that was bitter, but the people. The Israelites had an attitude of bitterness. This caused them to feel that the water was bitter.
It has been said that everything in psychology that is valid can
be found in the Torah. This is a prime example.
People who suffer from clinical depression may have distorted
sense experiences. Their food may taste bad. Mild discomfort may be felt as excruciating pain. They may see all reality as being dismal, just as one who looks through dark glasses cannot see anything as bright.
The Israelites repeatedly grumbled at being in the desert. Their
food, the manna, was miraculously supplied daily from heaven. Their clothes grew with them and never wore out (Deuteronomy 8:3-4). Yet, they said
that they were better off as slaves in Egypt (Exodus 14:12).
With this attitude, even the sweetest water
can taste bitter.
Some people who are dissatisfied with their lives may seek to make
changes in their external reality. They may change jobs or relocate. They may blame their unhappiness on their spouse and divorce. Very often they are just as dissatisfied with their new situation.
If we feel that reality is unpleasant, we would do well to
evaluate ourselves. The reason for the unpleasantness may lie within ourselves rather than in our external reality.