One of the most evil things: let the user type for 15 minutes and blank out his textbox

That's one of the most evil thing a webpage can do to a user.

Let the user type for 15 minutes for the blog, and then when somethings is wrong: maybe a JavaScript error, or server error, then simply blank the whole textbox out, and let the user re-type the whole content.

Have you had that experience here or in other website?

Funny thing, sometimes I mentioned that in an interview, and the interviewer sounded like they don't care at all.

And this kind of things are still happening, including dev.to

I think it happened to me because of some server error, or somebody pushed the wrong JS to the site causing a temporary bug.

Tell us if you have similar experiences, or what you consider one of the most evil things a webpage can do to you.