I am sure it's only me, totally personal and I know it's not right, but I put a lot attention to picture quality such that I'm starting to get disturbed almost every time I see flaws in a photograph. Contrary to that of, well, hipster-souled photograph lovers, I see photos in the very details; way too much, and it's the problem. I agree, though, certain quality flaws do enhance the appearance of the photograph, especially adding nuance and mood.

I take the best of both worlds: do just the right amount of the flaws to the right kind of photographs, hinder doing so to the other kind; because there's never the right thing for everything. If I want to add moods, I would just add the suitable quality flaws (aka. effects).

What are these effects?
Blown highlights: this kind of flaw make photographs look as if they were taken with a web cam or a phone. The picture would look cartoonish, in certain conditions, because cartoon is supposed to feature less details. Of course certain conditions do look better with the light sources presented as pure white; but a photograph of snowy scenery which mainly consists of white, would look better with the snows presented with details instead of pure white. Details matter, you don't always draw comics with your camera. I never do.

Chromatic abberations: This flaw is caused by the lens. I never see this kind of flaw as acceptable; unless the amount is too high, e.g. from a certain fisheye complete with its blurry corners, that makes it look artistic. For regular lenses with very little but noticeable abberations, the flaw simply ruins the photographs by adding unwanted colors in several areas; while never benefits anything. For example, a lush vegetation in the far background with some rainbows at the foliage. You use polarizer, right? you want to get rid of those reflections from the leaves but lens abberations simply add other kind of unwanted features.

Vignette: with the right amount, to the right composition, you could have a photograph that more firmly conveys the intent, corroborating the subject. Suitable for photographs showing very few features, or with background that is too busy. As post-processing effect, better to be applied on photographs with mixed lighting sources. Use sufficiently, unless you would want a pinhole-camera effect.

Inaccurate white balance: modern digital cameras start to show even more accurate colors reproduction, making skin tones look realistic, colorful fruits look just as vivid, and your car's paint look just as sporty; but sometimes, as I experienced myself, inaccurate colors look good for certain compositions. Do even movie color grading—immensely discard main colors, leaving certain tones to the photograph. Remember, only to certain photographs, e.g. your friend in the middle of a strange place. You don't do this for food photography. As for white balance to handle fluorescent light sources: it's never acceptable to have green faces. Make sure the right white balance for those kind of situation.