Technique
Switch / fakie
Riding with the opposite foot forward from your natural stance.
Switch (also called fakie) means riding in the stance opposite your natural one, so a regular rider rides with the right foot forward and a goofy rider with the left. Riding switch is a difficulty multiplier: every basic skill must be relearned in the unfamiliar stance, and many tricks are named or scored differently when done switch.
For competition and progression, being able to ride and trick switch dramatically expands a rider's repertoire, since it effectively doubles the catalog of maneuvers available.