If someone who's crazy is "off their rocker," what do you say about a normal person? Are they on their sofa? Like, "Oh, my friend John totally has everything together. He's really on his sofa." But what about people who don't even have a rocker? Or a sofa? I won't mention any names...ahem. (Is it self-evident or what?)
Anyway...my apologies for the random lapse of intelligence. Just chalk it up as end-of-the-quarter syndrome. It's obviously that time of year when the mind gets tricksy on us...damn those tests!