Me, snapped by a student last night:
The Nikon D80 camera is on manual. That means aperture and shutter speed are set manually, but it does not mean that the flash is manual!
The flash is still fully automatic – the camera fires a preflash, measures light return, and sets flash power for the actual flash accordingly. We call that TTL (iTTL, part of CLS, for Nikon; E-TTL II for Canon). The flash was turned back toward the ceiling behind the photographer:never fire straight into your victim’s face if the flash is the main light source.