While this wasn't technically a real client, it's still one of the most insane requests I've ever had.

I chose to specialize in software engineering for the last year and a half of my degree, which meant a lot of subjects were based around teamwork, proper engineering practises, accessibility, agile methods, basically a lot of stuff to get us ready to work in a proper corporate dev environment. One of our subjects was all about project management, and the semester-long coursework project (that was in lieu of a final exam) was to develop a real project for a real client. And, very very smartly, the professors set up a meeting with the clients so that the clients could tell us what they wanted with sixty-odd students providing enough questions. They basically wanted a management service for their day-center along with an app for the people there. One of the optional requirements was a text chat. Personally not something I'm super interested in doing but whatever, it's a group project, I'll do my part.

The actual development of the project was an absolute nightmare, but that's a story for another day. All I'll say is that seven juniors with zero experience in the framework we chose does not make a balanced dev team.

Anyway, like three months into the four-month project we've got a somewhat functional program, we just need to get the server side part running and are working our asses off (some more than others) when the client comes in and says that 'hey, nice app, nobody else has added the chat yet, but could you do voice recognition okay thanks?'.

Fucking.
Voice.
Recognition.

This was a fucking basic-ass management app with the most complicated task being 'make it look pretty' and 'hook up a DB to an API' and they want us to add voice recognition after sitting on their ass for three months??? The entire team collectively flipped its shit the second they were out of earshot. The client would not take no for an answer, the professor simply told us that they asked for it and it was up to us whether we delivered or not. Someone working on the frontend had the genius idea of 'just get them to use google voice recognition' so we added the how-to in the manual and ticked the requirement box.

What amazes me about all that is how the client probably had no idea that their new last-minute request was even a problem for us, let alone it being in a completely different ballpark in terms of implementing from scratch.