One Christmas eve night, it must have been when Christmas came on a Sunday, I was listening to my bedroom system, and noticed a distinct change. The music sounded so good I couldn't stop listening. No, I hadn't been smoking any "wacky weed", popped pills, or drank Scotch; I was stone cold sober. It was daylight when I stopped listening, and that was only because I fell asleep.
Think about it, if there is no traffic on your electrical grid, you have perfect AC, and there could not have been a quieter time on our electrical grid than Christmas eve, when Christmas came on a Sunday.
There are so many variations from one grid to another, that one size can not fit all.