This baby, Hari das, starts crying every time his father stops chanting the mahamantra :-) (2 min video)
Caitanya Bhagavatam Childhood Pastimes of Lord Caitanya: Lord Caitanya would cry with tears coming out of His lotus eyes but as soon as He would hear the Holy Name then He would stop. So in this way He would always cry until they started to chant the Hari Naam. So in that way everybody would always have to chant Hare Krishna. As soon as they would stop, He would start to cry. They would then again chant! In this way He kept everybody chanting.
Watch it here: https://goo.gl/o4YK9O