Buck Vantage Force Pro. Chippy, absolutely terrible fit and finish aside from the scales, and the stop pin and liner are made of cheese so the knife wears out quicker than any other knife I've owned. I should have known not to give internal stop pins a chance on a "heavy duty/tactical/whatever" knife again though.
It's a cheapy, but the Enlan EL01. Everyone talked it up, but this knife is garbage. Terrible action, terrible grinds, terrible fit and finish, and heavy but failed a weak spine whack test on my hand. Add the non adjustable pivot and I feel bad for people who think these are a good budget beater. You're missing out on a lot.
Kershaw Thermite. Possibly the flimsiest frame lock you can buy. Seriously, is the over travel stop cut from a pop can? The action is terrible, and being assisted is the only thing that covers it up. Which it has no detent, so when that spring breaks the knife will be happy to open in your pocket. The spanto grind is a combination of the worst features of a tanto and a spearpoint. The grind profile also make it like cutting with a brick despite how shallow the blade is. Another highly recommended budget blade that makes me wonder how low people set the bar for cheap knives.
Spyderco Endura. Cheap plastic scales, and blade play. Non adjustable, constantly getting worse blade play. It's been many a year and I may not be remembering right, but I'm pretty sure mine had an integrated plastic pocket clip that ended up losing all tension too. One of maybe 5 knives I threw away because I thought it was dangerous. (This was before the Internet and easy company contact.)