What’s the worst piece of technology you’ve ever owned?

Depends on when it was produced.

My 1998 HP 4050DTN is still going strong, an absolutely bulletproof beast of a machine. Plus, I can get extra-stuffed cartridges for it that can do 20,000 sheets at 5% coverage. Even after two degrees and a quarter century I am only on my third cartridge.

My HP 5000DTN wide-format printer is much the same.

Of course, this was years before the DRM enshittification path that HP started down, so there is that.