The worst ones I’ve experienced:
A pair of old wire strippers my grandmother cleaned out of a drawer at her house. Don’t know where they came from since gramps always bought good tools, or perhaps it’s just that the design of these have improved over the years. Anyways, I never used them because I had a better pair, but I don’t like throwing away tools. So after years of being in my truck and then the bottom of my toolbox, I tried them – horrible. The cutters wouldn’t cut through 18ga stranded copper, and if you tried stripping the insulation the wire just wanted to jam between the two halves of the tool. Imagine like cheap scissors. Might not help that I’m left handed, but this is one of the few occasions I have garbaged a tool.
I was given a bit-type screwdriver set when I was about 13 or 14. I think it was a bonus item my Dad had picked up for free, and gave to me. The kit had two separate screwdrivers in it, oddly enough one was a ratcheting screwdriver with hex bits, and one was a fixed type with collet bits. The one with the collet-type bits is actually decent, but the ratcheting driver is horrible. It has several problems:
1) Just 10 teeth in the ratcheting mechanism is nowhere near enough for any tool, but especially not for a screwdriver.
2) The ratchet mechanism is below the handle, not built into it. So with a hollow handle, the balance feels wrong, even if the handle is filled with bits.
3) The switch for forward/locked/reverse tends to shift on its own.
4) The cover on the end of the ratcheting section tends to unscrew itself.
5) There is a flex joint between the ratchet mechanism and the handle, the idea being that you could use it as a regular screwdriver, or turn the handle by 45 or 90 degrees so it’s more like a pistol-grip screwdriver. Apart from the shape of the handle being wrong for this, the lock to keep it at 0 / 45 / 90 degrees tended to loosen itself off.
I kept the bits and sockets that went with it, but use them on a different screwdriver handle.
My sister-in-law had an experience that probably tops them all. She was helping someone build a fence, and they had bought some extra claw hammers. So they went out, and started pounding, and on the first nail the head of the hammer broke off. Then they tried the next hammer, and broke the claw on it immediately. The guy had bought stuff from a dollar store, and claimed “it was a perfectly good hammer.” Yeah, right. My sister-in-law was not at all amused. She’s not a tool person, but does know you get what you pay for.