In general, it is appropriate to adjust the brightness, balance, or contrast, but only if the entire image is adjusted equally.
Each pixel should be adjusted linearly. All bands or features evident in the original image must still be visible; do not adjust the image to the point where some parts of it disappear.
All seems to get what they want, and that takes money. Take for examination all the ciggeratte advertisements. Something as simple as a ciggeratte advertisement says a lot about ourselves. We value looking good, baseball good, all the time.