As the name suggests, they're always sad. Usually they're pessimistic, lonely and bored. If a Giggler turns into a Sobber, they usually hide their face so that they wouldn't be seen as an outcast. If they're exposed to enough fun and happiness and the like, they'll slowly turn into a Giggler. If a Giggler spends too much time in Frowntown, they'll slowly turn into a Sobber. Rather simple stuff, I reckon. There's also a stage in the middle of conversion, that being the Mezzo.