Straddling the edge of the hinge we find a set of touch-sensitive controls, including a power button and one-touch access for mute, WiFi, volume controls, LED backlighting and a few keyboard status lights.
It's my cue to be careful -- to steer clear of red wine and sugar, two sure triggers when I'm in that sensitive state, and to get enough rest since lack of sleep can tip me over the edge, too.