on the down side, if you work on one too long, it fries those particular cones in your eyes pretty good, at least in the case of green and if the contrast is to

on the down side, if you work on one too long, it fries those particular cones in your eyes pretty good, at least in the case of green and if the contrast is too high.. my daily driver is grey-on-black these days for that reason, though I keep a warm-and fuzzy green-on-black with vt220 font and slow-baud emulator around for the occasional one-off shell command.