I think there's 2 essentially different processes that are being melded into the one heading of "post processing" - I cheerfully confess that my view is formed from having spent years using film - we can draw similarities between film and digital processing, but in my view they are often inaccurately framed (deliberate pun!)......
I'll try to extrapolate - most of what I shot on film relied on me "getting it right in camera" in the first place - so there was no need for individual hand-printing - you made sure the focus, exposure and framing were "right", so that when the results came back from the processors you could go through the prints, bin the closed eyes or occasional "missed focus" shots - job done!
You'd choose the film for it's characteristics (usually based on things like colour rendition, fine grain, speed and "latitude"), and you'd choose your processor for their ability to consistently process the images, perhaps to input your preference (in my case, "slightly warm, slightly dense") - you then gave them a pile of exposed film, and "left them to it" - essentially, your job was done........
Nowadays most people have to try to mimic that part of "processing" themselves, sweating over a computer to do so - to be frank, I find it boring in the extreme, and would cheerfully return to letting a good lab do it for me.......
That's one part of "post processing" - then there's the part that irks me, and I suspect a lot of other people - it's when simple "optimisation" is left way behind, and images enter the land of "computer faffed imagery" where the simple craft of photography is left behind, and all sorts of gimmickry is used (rather like the worst of Cokin's filters/soft focus/superimpositions - as someone almost remarked "images on acid"). Perhaps I'm being a sensitive little flower over it, but I do resent "effects" when they're visible - many a time I glance at the TV screen to see over-use of grey grads, to over-damp down the sky..........
I had many "goes" with the original Photoshop over many years, and came to the conclusion it was probably the most ghastly, unintuitive piece of software ever made - I get on far better with The Gimp, but really do not enjoying post processing at all - it's a necessary evil these days.......