TL;DR;
If you're asked to do something you believe is wrong - speak up. (I'm talking about workplace, but I suspect it can be generalised.)
Actively try to Right the Wrong.
Either work harder - and learn why it's not Wrong - but actually - it is Right.
Or work harder - to explain to your partners why it's Wrong.
If both fail, escalate.
(There are exceptions, but this is the rule.)
Make a Difference. Be Involved.
Longer Story
(I'm writing about a specific case involving Product Managers and Software Developers - but feel free to replace with any two names/roles/people you can think of. This Is Truth.)
Recently, I was involved in a discussion at work involving some product crisis-and-resolution.
Once the crisis was resolved, we ran a retrospect/post-mortem - analysing the steps leading to the crisis and it's resolution, to see what we can learn to decrease chance of such crisis from happening in the first place, and how to better handle a crisis when it does happen.
At some stage, one of the developers said:
"I told the Product Manager that this may break, and we should instead be doing that, but the PM insisted".
When asked "And what did you do?", the developer answered "Well, I knew it was wrong, but the PM insisted, so I went ahead and did what the PM asked, despite my conviction".
That's when we knew (part of) what broke - and what (once fixed) will decrease chances of crisis, and increase chance of quick remedy and minimal impact on users - once the inevitable crisis happens...
When you're part of a team working on something (example: a developer working on a product) and you're asked to perform a task you believe to be wrong (example: develop a solution that you are convinced work work/scale/etc.), you must speak up.
TL;DR;
If you're asked to do something you believe is wrong - speak up. (I'm talking about workplace, but I suspect it can be generalised.)
Actively try to Right the Wrong.
Either work harder - and learn why it's not Wrong - but actually - it is Right.
Or work harder - to explain to your partners why it's Wrong.
If both fail, escalate.
(There are exceptions, but this is the rule.)
Make a Difference. Be Involved.