Or do what I do, express yourself like a human instead of a business machine, leave, go do the rejected right thing for a competitor, and send the product brochure to the people who cared more about their feelings than the work.
You have to be willing to do a lot of walking away, but the inevitable "you were right" has been satisfying so far.
Or I guess another way to say it is if you can, do, and if you can't, by all means, coddle. Just hope I don't end up across the table from you.
This is super passive aggressive, like a child saying "I'm leaving, you will miss me guys, you'll be sorry, you'll see I was right and I'll be the one laughting !".
Besides, this assumes people rejecting your idea are bad, while they are just being humans. Humans are weak unefficient creatures, it's no use to take offense in it, we all are weaks in some areas.
Or you could accept the situation for what it is: blind ignorance on the part of a leader. Then you can merrily do whatever's best for you without carrying around anger toward them.
Choosing to get offended is rarely a quick path to healthy productivity.
You have to be willing to do a lot of walking away, but the inevitable "you were right" has been satisfying so far.
Or I guess another way to say it is if you can, do, and if you can't, by all means, coddle. Just hope I don't end up across the table from you.