BG 18.37-39
Which at first is as venom but in the end is as nectar; that pleasure is said to be pure, born of the blissful knowledge of the Self. That which from the union of the senses with their objects at first is as nectar, but in the end is like venom, that pleasure is accounted passionate. That pleasure which both at first and afterwards is delusive of the self, arising from sleep, indolence and heedlessness, that is declared dark.