In my day, we didn't have fancy liquid crystal displays, capable of displaying millions of colours. We didn't have responsive touchscreens and microphones that one could blow into. We had shitty games with a half-dozen LEDs that forced one to use his or her imagination and we liked it. Actually, they were all crap and we hated them. Playing "Football" with an electric wire that glowed with just visible brightness on a pure red field was exciting for about the first 2 minutes. Crap controls, no visuals whatsoever, even calculators disguised as games—the late 70s and early 80s were handheld hell.
Fortunately for those of you who don't know how good you got it *pounds desk* John Sadowski has collected a non-exhaustive but often amusing list of the weirdest to worst early electronic handheld games. From Touch Me by Atari to Pythaligoras, it's a retro parade of sleep inducing gaming.
Any list that starts with Naughty Squirrel demands your attention.