[My_Name]

Often, a user presented with a progress bar will wait much longer without frustration than a user without one will do. Sometimes, making the code faster is non-trivial and is not cost-effective when compared to making the user simply not complain.

[marginalia_nu]

Latency is weird in UX. Being too fast can also be jarring.

If you hit a button that's supposed to do something (e.g. "send email" or "commit changes") and the page loads too fast, say in 20ms, a lot of users panic because they think something is broken.

[actionfromafar]

Very true. And it sort of indicates that it is broken or at least unusual. If sending an email at least means "my email server has it now", then 20ms for that to happen would be a very unusual setup.

So if the dialog closes in 20ms if likely means the message was queued internally by the email client and then I would be worried that the queue will not be processed for whatever reason.

[NebulaStorm456]

Similar to the fact that humans need enlarged, human scale-size input and output mechanisms (keyboard, mouse, smartphones, control panel buttons in cockpit). The actual meat of the computation can be packaged in a nicely small form factor.

[mjr00]

I remember reading a long time ago that one of the big online tax filing sites, probably TurboTax, added a bunch of loading bars with messages like "Calculating your optimal return..." because users didn't feel like it was trying hard enough when it finished instantly.

[CyberDildonics]

The solution is user feedback, not rationalizing making software slow to use a scripting language or electron or whatever other shortcut that is bad for a user.

[ethmarks]

Is there a term for this kind of psychologically-targeted UX design?

For example, having a faster-spinning progress wheel makes users feel like the task is completed faster even if the elapsed time is the same.