>A good example are pages that take 5 seconds to load because they have to do so much, then you submit a form, and the page reload takes 5 seconds to go through but there is no UI feedback so you press the button a few more times because maybe it didn’t work? Then you get an error because the first action worked but the subsequent actions failed due to uniqueness constraints.
It's been standard practice for at least 25 years to disable the submit button once it is pressed. If you aren't doing this as a developer, you are practically begging for trouble, and it's really so easy to avoid that trouble.
Lots of people build stuff and don’t have 25 years of experience. Or it seemed like “unnecessary complexity” when the app had 5 users and interactions took 100ms.
A lot of standard things feel like “wow people are way overthinking this, it’s so easy” when you have 5 users :)
It's been standard practice for at least 25 years to disable the submit button once it is pressed. If you aren't doing this as a developer, you are practically begging for trouble, and it's really so easy to avoid that trouble.