A unit's thoughts and experiences cause knots to form in their g-strings. Dreaming is a side effect of the process of untangling them. Additionally, a unit's senses gather more information than they are able to process. Sleep helps make sense of them and is also part of the learning process. By sleeping, units are perform better when they wake up on their next turn.
Thinkamancers are able to perform this process consciously and dispassionately. They have full control over their thinkspace when they do it, and as such do not have to worry about nightmares. Though Thinkamancers lucid dream, they cannot recall dream memories without spending juice.Hvs.tCF 159