I don't know, personally. Here's a list of what's considered crap and my take on it:
Jaguar sucked, the CD add-on was sporadic.
3DO was $800 and had no games.
Sega CD I've never played (even though I have one) (I blame its failure on the reliance on FMV games, if they pushed the others [Snatcher, Lunar, Sonic CD]), and the 32X is surprisingly good. Virtua Racing and Knuckles' Chaotix kick ass.
CD-i made a mockery of Zelda and Mario.
Virtual Boy: The games released in North America is less than my age. Also, caused various problems.
Now, the worst ever made has to be the Gizmondo, a portable system. Imagine yourself playing your DS or PSP. Then, after finishing a boss, an ad pops up. That was basically the Gizmondo's plan on cutting costs. With ads, it was $230 (still $70-$100 less than its competition). Without, $400 (I'd rather get a next-gen console for the same price, thank you). The planned GPS never came to fruition, and only eight games were ever released out of the 14 planned to be.