They have a property analogous to electron spin in that they actually have 4 orientations. Wrong way 1 --> spin 180 degrees --> wrong way 2 --> spin 180 degrees --> wrong way 3 --> spin 180 degrees --> right way. They also have a Heisenberg thing going on in that if the port is unobserved, there are an infinite number of incorrect orientations, and just one, statistically unlikely, correct orientation. Spinning the computer to observe the port collapses the wave function, but 6 other cables will fall out.
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It is not the lack of reversibility that is unforgivable, it is that they LOOK and FEEL like they are reversible with no obvious clues to the correct orientation.
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Even a fool-proof shape doesn’t guarantee success.
A friend once told me the story of a customer who inserted a DB25 serial connector the wrong way round.
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Yep, anybody old enough to remember bending the pins on a parallel cable and having to spend an afternoon and $25 to get the stupid printer to work will happily flip and reflip a USB plug.
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This is truth. So many pins I had to rebend, and then explain to the customer what they were doing wrong.
For those extolling USB-C, you’re right that the form factor is better. I’ve just never seen a USB-C docking station that wasn’t rife with issues, like monitors suddenly stop receiving feed. Simple solution is to unplug/replug the dock, but it’s still annoying. It’s been a bit over a year though, so maybe things have improved there.
DB25, USB-2, USB-C, parallel ports, PS2. . . I am sooooo glad I finally got out of the IT repair industry after twenty plus years. It’s y’all’s problem now, not mine. 
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One acronym:
SCSI
That, and though FireWire was better, only Apple really supported it, and Apple was the critical mass that USB needed to get going. Ditching the ADB, SCSI and Apple Serial ports was a good thing, and the flat design of USB was another factor in its long life.
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I remember those Centronics connectors where it snapped in nice and then you flipped up a couple of paperclip looking wires to lock it in place. They were bulky as hell but really nice on the hands. Much less annoying than the screw in strain relief on DB9/DB25/HD15 connectors.
Or the old AUI ports where you plugged it in and then slid over a small metal bit to lock the connector in place. Those were fairly compact but had the same problem as the DB connectors where you had to be careful not to bend the pins.
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When Ajay Bhatt dies, they’ll gently lower the coffin, then pull it back up, turn it the other way, then lower it again. (original joke source unknown)
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The PS/2 connectors had a capture and a key. Seat it gently against the socket face, spin it until the key seats. No bent pins.
The big Centronix parallel plugs were easy to seat. The screw-in serial port strain relief on DB9/DC15/DB23/DB31’s was a minor annoyance, but you weren’t plugging and unplugging them all the time.
I remember connecting mainframe cabinets together with cables with big round Amphenol connectors.
And I’m not on your lawn.
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I may have a box of all of those still. I should probably get rid of it now.
When I plug in a power cord, I actually use my fingers to feel that the blades are in fact going into the correct sockets.
By design, the USB logo on the plug should face up.Of course, this only works if certain manufacturers didn’t turn their sockets 90 degrees.
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yeah the ps/2 connectors did not have much pin bending problems but if you were off just a little you might have to twist over the thing several times, at least as bad as a usb. They were pretty good once they were interchangeable. The centronix plugs were pretty good, but huge. You would not want to carry one in your pocket, much less have one on your nice thin computer. Yeah the screw in serial (and other) plugs were no hastle if you dont remove them but the same can be said about usb. Also god help you if you had to remove one of those old cables from a nest of other cables. The screws worked like anchors. One of the huge benifiets of usb is the removial of big plugs from your laptop.
I know you arn’t on my lawn but all these other wipper snapers…
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Yeah, be carefull doing that. I have gotten shocked that way.
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ive never minded them. dont they have that channel pinch on one side? you just lightly press and rotate. and at least it was obvious that the port was always the same direction.
on usb, you can see the port is horizontal or vertical facing - but there’s no visual clue to which way is “up” for the plug. not that it matters because the plugs don’t give you any info either.
the best plugs imo are round. especially rca and audio jacks. stick it in. done. the color coding that’s evolved to indicate which goes where seems to work well enough.
[edit: ack. @kennykb beat me to it. ]
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Indeed. People complaining about the minor annoyances of USB-A plugs probably never wrestled with serial/parallel port plugs. Or even worse: “pass-through dongles” used by some programs as copy protection.
USB-A wasn’t perfect. But it was a lot better than most things it replaced.
I still like the sturdiness of USB-A plugs. Micro-usb, and also USB-C plugs are rather sensitive to snapping.
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First thing I thought of, the most annoying part is the lower than 50% chance of correct insertion.
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I do not wish to be reminded of IRQ conflicts thank you very much.
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Yeah PS/2 plugs were nicer then the serial ones they replaced. They only went in one way and if you had them lined up right it was pretty easy but if you did not have a nice case that guided the plug properly you would have to scoot it around while twisting. The point is there was some fiddling around which is more or less the problem with USB. Also you could bend the pins, it was harder to do then serial but I’ve seen it. I am not sure why you would know that the port was the same direction.
Round plugs with no orientation, like headphones or RCA are clearly the nicest sort of plug, but it is hard to have enough connections, I suppose.
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