I'd add that I've noticed older people struggling with hidden UI elements. (E.g. not knowing that button X will appear if they do Y (and then not remembering if told...)).
Peek-a-boo UI is incompetent. It's even dumber when you consider that, in most cases, the space for the disappearing controls has already been reserved; so nothing is gained by hiding them.
And almost as bad as peek-a-boo UI is "flat" UI, where most controls aren't demarcated as such. So you're reduced to clicking on plain text labels and other inert-looking components to see if there are hidden goodies associated with them. Absurd.
This is age-related only in that that it's about visual cues, which are the entire point of GUIs to begin with. Physical buttons on a device are inherently discoverable, as were the controls in GUIs for decades. Younger people are used to the incompetence of newer designs, and more tolerant of having to click every pixel on the screen to find things. It's unfortunate.
The bright spot is that there has been some backlash against the "flat" laziness and a return to some visual cues.
I was testing a web app out on my dad and he dragged the cursor to the bottom of the screen, which brought up the Mac Dock which immediately confused him and he asked my why I did that. I am not sure how to code around just general inability to use a computer, maybe avoid elements at the edges of the viewport haha.
These days, things are pretty much "stupid proof." No matter how many times I insist on it, people my parents' age simply refuse to believe that there is nothing they could reasonably type or click while using their computer that will irreparably harm it. (Yes, of course they could somehow format their hard drive, etc, but there's zero chance you'd be able to do that on accident.)
I don't agree with this generalization. Here's an example: A stereo receiver, even today's A/V receiver, has a certain number of physical inputs. Back in the day, you had buttons on the front to select the input you wanted, clearly labeled. One press gets you the source you want, every time.
Many receivers today force you to press an Input button or turn a wheel to iterate through a list of inputs, a list of unknown size and unknown beginning and end. This is because the display idiotically doesn't show a complete LIST of the inputs at once, or even a moving dot to show you where you are in the list. So you could be one input below the one you're trying to select in the list, but if you happen to turn the dial the other way you'll go through 10 inputs to get back to it. Granted, this is much less commonly encountered now because nobody is going over to his receiver to put a disc in the player, but it was a problem for many years when people were still doing so.
In some cases, older designs were also better for safety. When safety is on the line, the best design (or at least universally-understood standards) often percolate to the top and stay there.
A sad example of this was Jeep's attempt to "innovate" with a disastrously defective gear shift, which killed Star Trek actor Anton Yelchin: https://www.theguardian.com/film/2016/jun/20/star-trek-actor...
But I also acknowledge that there have been major safety improvements. The other day I rented a chain saw for the first time and was comforted to see the safety brake on it.
> people my parents' age simply refuse to believe that there is nothing they could reasonably type or click while using their computer that will irreparably harm it
Another example is that our last TV had a "Source" Button. But it doesn't change the source, it brings up a list so you can choose a source. Nearly every week she would accidentally hit Channel Up or Down on the TV remote and then not know how to switch it back to the Cable Box. She'd hit Source and it wouldn't change the source and then call me.
Sadly, she has dementia now and will never learn.
This is an anti pattern which good directly against the concept of "affordance."