Ooooohhh...I have a couple!
Sadly as a teen I was into the Realistic stuff, and the SA-1000A integrated amp was fun when I bought it but, once I built the Hafler DH-101 in 1982, I heard how truly awful that piece sounded. Its bass was weak, and it slurred all the high frequencies.
Most Sony disc players I've ever owned have lasted a year or two, and died. And more than half the time, it was the danged loading mechanisms that would fail. Needless to say, no more Sony if I can help it.
More recently: a Rotel RB1070 power amp. Nicely built, but it was the most sterile and bland amplifier I've ever heard in my life. Not only that, despite its power rating being only half the previous amp, it sure didn't have the cojones. Seemed to run out of gas quickly. Granted I got it free, so no loss there, but after hearing all the raving about how "great" Rotel is, it left me with a really bad impression. I even stopped using my system for a while. The amp I replaced it with is a Nelson Pass design, and it was nice to have something much more musical back in the system.
And I can't say I'm all that impressed about the design flaws in the Pro-Ject Xtension 10...not for the criminal amount of money they charge for it. Thankfully I got it at a cut-rate deal (brand new). I really want to move up to a Clearaudio (don't like the VPI sound, sorry), but nobody will take this thing off my hands...not without my taking a bath on it...