Edit: I misread the question. I thought it was “lowest quality product that you still use” (I was distracted)

Original comment: Harbor freight calipers. Surprisingly still accurate and undamaged through years of abuse. Kind of amazing, and shockingly useful.

I bought a harbor freight heat gun. All I’ll use it for is lighting charcoal. Very uneven heat, and will melt itself if you don’t turn it nozzle up when you turn it off.

1985 Pontiac Sunbird and my parents had a 1986 Buick Skyhawk. Both were exactly the same car, just different front fascia. Same crappy 1.8L SOHC engine and terrible build quality.

Both cars blew head gaskets at 50,000 miles and my Sunbird blew it again at 65,000miles. Neither car were ever overheated. The A/C on both cars died at 60K. Various parts of the exterior and interior were just plain falling apart. The cars’ performance was absolutely abysmal.

The cars were so bad that I haven’t purchased another GM product since, nor will I ever buy another product from GM. My Dad had bought a mid-90’s Oldmobile 88 and it was actually OK for the most part. It just ate alternators, until I convinced him to put an upgraded aftermarket unit on and that problem was solved. Later he bought a Chevy Traverse and that thing was an absolute piece of trash. He had to put timing chains on it at 70k and that was a $2500 bill. The power steering also went out on it multiple times. He had the steering rack and power steering pump replaced multiple times.

I traded my old Sunbird in on a 1985 Toyota Corolla GT-S and THAT was my absolute favorite car of all time. I autocrossed it for several years and it never broke. I’d love to find one to restore. I have owned multiple Toyotas in my 39 years of driving. My current car is a Camry Hybrid.

Quip was pretty awful compared to Sonicare.

Just about anything by Betterware. The one that sticks in my mind was the non-stick stick-on hook that lasted for all of a minute before falling off under its own weight. I ended up second guessing how the thing they were selling could possibly go wrong, and if I could think of something then I wouldn’t get it.

There is one Betterware item that’s lasted the years though. A hair trap for the sink. It’s a metal disk with holes punched in it. Hard for that not to work, really.

Also, increasingly, tat off Scamazon.

Cheap mini Bluetooth keyboard. It kept disconnecting and missing keystrokes. Input latency was awful too. 2010s Bluetooth was so bad

Can I nominate an airline?

Microsoft Surface.

In no particular order:

The Al Cantera keyboard cover stated delaminating and the top layer started peeling off just from the friction of resting your hands on it. Started happening within months of getting it.

Battery failed after just a few years of daily use, I’m talking completely refused to charge, you unplug the charger even after leaving it in overnight and the screen goes black instantly. And while most laptops can run just fine with a dead battery as long as you keep it plugged in at all times, not the Surface. The little magnetic connector supplies so little power that the device is basically forced at down clock to below 1 GHz to keep from shutting down due to undercurrent. And sometimes it shuts down anyway because fuck you.

It’s also glued so tight that you basically can’t open it without destroying the screen in the process.

Also, the magnetic charge connector started having contact issues, so the moment you bump it, it disconnects and causes the device to turn off. It also just refuses to connect half the time when you plug it in. Gotta jiggle it, blow into it, shake and hit it a bunch of times, and pray. I’m pretty sure it’s the tablet’s side that’s the problem because changing chargers did nothing, and the charger that came with the problem tablet worked fine on another Surface. Gotta love when companies make the fragile part of the connector apart of the $2000 device that’s sealed shut with glue and put the more robust part on the cheap and easily replaceable charger.

It’s also really bad at going to sleep. Way too many times I’ve closed it, put it in my bag, and when I take it out it’s scalding hot and the battery is nearly drained. It’s your own device Microsoft, running 100% your own software. How the hell do you fuck it up?!

I did buy a number of fake flash drives, so they’re definitely up there. Luckily I’ve always won the disputes and got my money back from every one of them.

There were also a number of headphones whose sound was so fucking bad, listening to stuff off my phone’s speakers was better

At this point, pretty much anything purchased on Amazon. Nowadays even stuff that looks like it’s from a legit seller can end up being a knockoff from a scam seller because of their warehouse storage logistics. Or they sell a high quality item long enough to get good reviews on the listing, then switch it out with some cheap piece of shit to take in the dough until the rating is tanked, lather rinse repeat. It’s just becoming more and more like Wish/Temu where the listings are straight up lies and they just rely on people not wanting to do through the trouble of a return.

A knockoff iPhone charger from China. I plugged it into my computer and it literally caught fire.

I purchased a hammer at a dollar store once, just to see how bad it was.

I found out when the head of the hammer flew off on a back-swing and put a whole in the wall. The neck of the hammer was made of flimsy, hollow tube metal and the head had only been tack-welded on in 2 places.

This was a few years back, before I knew this was even possible, but a portable hard drive off of Amazon. Not only was it sharp on all edges, it was only programed to show the storage without actually having it. I spent an evening “moving” docs from a dying laptop, only to plug it in the next day two find a fraction of what I thought I moved over.

Also, a yoga mat that disintegrated when I went to do a plank. Just pressing my hands into it was enough for it to flake apart.

A replacement PCV valve for my car.

Car was around 100,000 miles, figured it was a good time to do a big refresh & replace a bunch of stuff. Spark plugs, belts & hoses, fuel & air filters, fluids, etc etc… While I was at the parts store, guy suggested I also replace the PCV valve. But, it turned out the only one he had in stock was the store brand. $4, sure whatever. Got it home, took the factory one off the car, and sure enough it was gummed up kinda bad. But went to put the new one on, and it just about collapsed in my hands. It was so flimsy, kinda like a drinking straw. Ended up cleaning the factory one & putting it back on, threw the new one away.

A cheap USB 32GB pendrive. It would barely reach 1MB/s transfer speeds and started corrupting files almost instantly.