We tend to look for qualities and shortcomings of a person related to his material nature. We do not evaluate his spiritual nature. When we evaluate the material qualities, we inevitably see the shortcomings also. Where is praise, inevitably there is fault finding also. Therefore a sadhak must neither see one's qualities nor shortcomings. This is possible for a sadhak of higher level only. But at-least we must avoid evaluating others' shortcomings. Evaluating shortcomings is very bad for sadhak.
"Sapnehu nahi dekhe par dosha".
Sadhak never even dreams of others' shortcomings. This is a crucial part of bhakti yoga.
If your nature is fault finding, you cannot help seeing shortcomings, then just remember back and see what faults and mistakes you have done from your birth. See your own faults first. If you evaluate yourself sincerely, you will find that you have hundreds and thousands of faults yourself. I'm talking about myself. There are so many faults in myself which I can't tell a single person created by the Creator! Not even my own mother, not even my Gurudev, the most spiritually intimate person. When we ourselves are so faulty, how can we evaluate and discuss the shortcomings and faults of others?
That is why in bhakti yoga we need to see the spiritual qualities of others and shortcomings of oneself.
A sadhak must observe others' qualities. There are qualities even in an ant. The discipline with which an ant works is something we humans should take lesson from. See qualities even in a
bird. If we could observe our surroundings and take lesson from them then we could increase our wisdom and develop to higher levels. Look how a crow has qualities superior to us. If you give it a bread it will not eat it first. It will caw and let know all its relatives that it has found some food. Not only that, if another crow is unable to come to eat for some reason, it will take some bread in its beak and go and feed that crow. It could have filled its own stomach first and then call its relatives but it doesn't do that. In case of we humans, if we came to know that something good is being given out, we would fill up to our own contentment and then if something is left, we would tell others! A crow also saves food for later but first it will call its relatives.
God has given qualities and shortcomings in every living entity. One has some quality, another has some other quality. One has some fault while another has some other fault. We see only what is obvious. Someone became very angry for some reason, we think oh this person has so much anger. I don't have anger like this. But who knows how much desire, greed, envy, cheating and dishonesty persists inside you? Others aren't aware of it so you are called a sadhu. That is why see qualities of others and faults in yourself. Always think ohh this person has so many qualities, I don't have a single quality. If I had a single quality then it would have made Krishna happy. We see one fault in others and we start discussing it. We don't see the numerous faults in our own selves. Who knows what superior quality the person has, but we are busy finding faults. Chaitanya mahaprabhu says,
"aninduk hoiya je sakrit krishna bole, satya satya Krishna tare uddharibe hele".
Meaning if one chants Krishna naam without discussing others' faults, Krishna will definitely take him out of the cycle of rebirths and give Premabhakti without much delay.
"Nirmal man jan mohi pawa, mohi kapat chhal chhidra na bhawa".
Those who have pure hearts reach me, I don't like deception, cheat and character full of holes, says Shri Ramchandra in Ram charit manas. What is the point in doing sadhana if we don't have the qualities needed to delight Krishna? We are chanting harinaam, doing tapasya, meditation and all but inside we are full of deception, flaws, wickedness, etc then how can we expect Krishna to be happy with us? How can Krishna dwell in a heart full of impurities? That is why it is very important to purify your heart. Become pure and simple. Let go of all the wickedness and treachery. Then you will go a long way up the spiritual journey in a very short time. Otherwise it might take births after births.