As Krishna describes the man of wisdom, he explains the characteristics of such a person.
duḥkheṣhv-anudvigna-manāḥ sukheṣhu vigata-spṛihaḥ
vīta-rāga-bhaya-krodhaḥ sthita-dhīr munir uchyate
This can be roughly translated to:
One whose mind remains undisturbed amidst misery, who does not crave for pleasure, and who is free from attachment, fear, and anger, is called a sage of steady wisdom.
– Bhagavad Gita 2.56
Krishna indicated earlier that people commonly are heavily influenced by their nature and their specific daily situation. Above, the characteristics of a man of wisdom (a muni) are described.
Such a muni is not disturbed by misery and does not crave pleasure. He is also not perturbed by attachment, fear, and anger.
Of course, this standard is difficult to meet if taken absolutely. However, in spite of imperfections, one can practice regularly to achieve this in daily life.