I know what you mean. My example was just randomly thrown together and was extreme to get a point across: Just how much you can do.
Obviously, grading can go whatever way you want: subtle, ott, and so on.
The thing with grading is, it's not just an add on. Grading is necessary to make your shots consistent. Unless of course you have a cinematographer who knows his way perfectly around lighting, different light levels, colors and frequences (to must amateur filmmakers, "lighting" is just a matter of wether something is visible or not, maybe create a shadow here and there - they're not even aware that light has different frequencies hence resulting in a different color scheme when picked up by a camera).
When images have their color schemes all over the place, it's obvious that the cinematographer didn't know about that and however well they are framed, the images will be let down by that because cinematography is much more then framing. And the audience will notice that it looks "different" from what they're used to see even though they won't be able to tell you why that is.
Grading isn't just a "filter" you add, that's correct. It takes several filters combined and a lot of playing around until you get what you want. As I said, you can go for any look you want. You can even take the "ungraded" image and take that as your look if that's what you're after. Then you will have to get through all the other shots and make them match.
Grading is about adjusting the contrast levels and the gradients and white balance to match. So that when you cut from one shot to another, it still feels like the "same scene" - if you know what I mean.
Everything you watch nowadays is graded. Cinema films, TV movies, TV series. Everything. Some are graded better then others, but they all are. So grading is nothing to avoid in order to "not look graded". Because grading doesn't describe a look, it's a process to "get" a look. Whatever look.
And yes, there's quite a lot of examples of grading gone wrong. Especially here in the cinema. Then don't take these as an example.
Hopefully that helps.
Good luck with the film