1. Srila Bhaktisiddhanta Sarasvati on sense gratification, good and bad

    Because of the activities of the senses, we become subjected to many sense gratificatory processes and are thus entangled by the laws of material nature.

    This entanglement is called visaya. When the sense gratificatory processes are executed by pious activity, they are called su-visaya. The word su means ‘good,’ and visaya means ‘sense objects.’ When the sense gratificatory activities are performed under sinful conditions, they are called ku-visaya, bad sense enjoyment. In either case, either ku-visaya or su-visaya, these are material activities. As such, they are compared to stool. In other words, such things are to be avoided. To become free from su-visaya and ku-visaya, one must engage himself in the transcendental loving service of Krsna, the Supreme Personality of Godhead. The activities of devotional service are free from the contamination of material qualities. Therefore, to be free from the reactions of su-visaya and ku-visaya, one must take to Krsna consciousness. In that way, one will save himself from contamination.”

    Srila Bhaktisiddhanta Sarasvati, quoted by Srila Prabhupada in CC Madhya 1.198 purport