In mythology, in the epic Mahabharata Yudhishthir symbolizes a person who has learnt the art of being in balance in loss and gain and the one who practices righteous living.

Arjuna symbolizes with the quality to focus and the quality to see only the eyes of a fish when focusing on the fish.

Bheema symbolizes with the power to fight the evil. Sahdev symbolizes with the quality of helping others and Nakul symbolizes with how to remain neutral in any circumstances.

The weakness of Yudhishthir was lust (gambling), of Arjuna was getting defocused due to any doubt and of Bheem (Bal) was getting instigated on tiny things.

A person who is too focused can easily get diverted by any doubt. This is what happened to Arjuna when the Kurukshetra war started. He was focused completely before and after the Bhagavad Geeta episode.

Bhagavad Geeta was a dialogue between Arjuna and Lord Krishna delivered when Arjuna was overpowered by doubts in his mind whether he should fight or not? Was he justified in fighting with his own people?

Once the doubts were removed by Lord Krishna using the principles of cognitive behavior therapy (as called today) he was a focused man again.

In Hindu mythology, Lord Krishna represents consciousness, therefore in any doubt one should redirect them to the heart/consciousness to take the right decision.