Nanda Mahārāj, the father of Kṛṣṇa, used to think: "In my pasturing ground the goddess of fortune is personally present, and I possess more than ten hundred, thousand cows which loiter here and there. And above all, I have a son like Kṛṣṇa, who is such a powerful, wonderful worker. Therefore, even though I am a householder, I am feeling so satisfied!" This is an instance of mental endurance resulting from the absence of all distress.
In another instance a devotee says, "I am always swimming in the nectarean ocean of the pastimes of the Personality of Godhead, and as such I have no more attraction for religious rituals, economic development, sense gratification, or even the ultimate salvation of merging into the existence of Brahman." This is an instance of the mind's endurance due to achieving the best thing in the world. The best thing in the world is absorption in Kṛṣṇa consciousness.
It is described in the Viṣṇu Purāṇa that when Akrūra came to take Kṛṣṇa and Balarāma to Mathurā, just by seeing Their faces he became so cheerful that all over his body there were symptoms of ecstatic love. This state is called happiness.
It is stated in the Tenth Canto, 33rd Chapter, 12th verse of Śrīmad-Bhāgavatam: "Upon seeing that Kṛṣṇa's arm was placed on her shoulder, one of the gopīs engaged in the rāsa dance became so ecstatically happy that she kissed Kṛṣṇa on His cheek." This is an instance of feeling happiness because of achieving a desired goal.