Taurus PT-111 Millennium - underwhelming accuracy, and magazine dropping into my hand if you even touched the release was pissing me right off. In fact, the only redeeming quality that gun had was it's size. Let it go for nearly 50% of what I paid. Lesson learned. Replaced by a Glock 26 and never looked back.
AMT Government - had to grease this thing up to where it was too slippery to even hold to get a full mag to work in it, and also use the hottest ball I could find. Uzi was it in the 90s. Finally let it go at a loss, with full disclosure. Replaced by a Colt Mark IV. Wouldn't mind having it back, just to get it to work properly, now that I have the time. Certainly, it was at least a beautiful gun.