It's not clear from your comment which context you presented it in. It's definitely embarrassing for people to have this sprung on them unaware, especially presentation-style in a big room. You gotta show people stuff like this in private, 1-on-1, in a very casual "hey, what do you think of this little hack?" kind of way. People are a lot more receptive in that context, and if they have time to go away and mull over just how much time you could save them, and help them get done, they might actually like it.
Fair point. I don't think I did it the crass way, but it's been quite a while and I'd tried to forget about the whole thing. I do remember showing it to a small group at first and getting the overall reaction of "but that's not the way we'd planned to do it!"
> In short, don't embarrass your coworkers.
This can't be overemphasized. And if you're in a situation where you have to decide between embarrassing your coworkers and going along with terrible ideas that waste time and money, then you may wish to decide to change part of the equation (e.g. removing yourself - or your coworkers - from the situation).
I don't think there is much you can do in these sort of situations. There is usually a layer of politics complicating things as well. Unless you are in a position to fire the team responsible then moving on is probably the best response.
To achieve a successful career, being good at navigating the complexities of people is often, if not more important than being good at navigating the complexities of code —- even in an engineering role.
In short, don't embarrass your coworkers.