An exceptional hack is a solution to a problem that while not very well thought out works beautifully in and of itself, doesn't break anything else and may be the source of many more solutions to more generic problems. If any hackers lived in Ancient Greece, they'd probably call these experiences divine inspiration, or perhaps the influence of a muse. Usually, it is only possible to create an exceptional hack during deep hack mode. All larval stage hackers wish they could create nothing but exceptional hacks.