You know, things were so much simpler before computers. I get a photo printed, hand the print to you, and I could expect that the image on the print didn't change during the exchange.

A simple way for me to understand GC and the need for it is with basic math. A pixel in an image is represented by three colors: red, green, and blue. Each color has a value between 0 ( black ) and 255 ( full brightness ) when represented using 8 bits/pixel. The problem is that CRT monitors didn't display the values linearly. If you had a red pixel with a value of 100 and another with a value of 200, you would expect the latter to be twice as bright as the former. This is not the case and while the extremes display close to linear, the midtones display dimmer. GC adjusts the colors, not by brightening the entire image, but by adjusting the different tones by the amount necessary to make them display linearly. As I understand it, LCD monitors do not suffer the same problem but are built to emulate it since everything out already accounts for it.

In a linear workflow, the texture maps need to be uncorrected because if you do a final correction during the render, those images will have been corrected twice giving it a washed out appearance.

As for my own renders, I use GC and also try to restrict myself to three lights in a scene.