Samskaras
Due to previous samskaras, one may be expert in some kind of activities, but purity is a different thing.
Staying Pure
1. Somebody asked Srila Prabhupada why so many are leaving? Prabhupada said,“You should be surprise if someone stays. It is not easy to stay because you have to stay pure.
2. Whatever you do, if purity is gone, character is gone, then everything is gone.
Bhakti gets Reduced
Many people do devotional service but commit offenses to other devotees. Then bhakti gets reduced.”
Hurting Krishna
Don’t criticise other devotees. It hurts Krishna.