Now this is a topic! Where to start?
IBM PCJr: good on paper but a terrible replacement for my Speccy. Still feel this one to this day as it was a LOT of money back then.
Lexmark inkjet printer, unknown vintage: Couldn’t tell you the model or when exactly I had it but it was just terrible. Lasted about 2 months. You don’t see them much outside of office machines these days.
ZIP Drives: In my first IT job we went fully on board with em, at the time it was mindblowing how much storage they offered compared to a floppy but the format died as quickly as it came. Had a couple of them fail on us but not as remarkably unreliable as I remember them being reported as being at the time.
More recently a HP Stream netbook: Wanted to get a cheap Windows machine for my son, but it was almost uselessly slow.