> - Blending colours is just a matter of linear interpolation.

I recall there being a particularly contentious bug report for Adobe Photoshop eight or nine years ago. The original thread is here: https://community.adobe.com/t5/photoshop-ecosystem-ideas/p-g... - but all the users have been replaced by "FeedbackCommunityMember", so it's a bit hard to figure out who is talking to who (perhaps someone can find a properly archived url).

In any case, an Adobe product person was unbelievably stubborn about their assumption there is just a single way colours can blend one to another, and that all the other ways couldn't possibly be desirable. It was pretty hard to read.