A pop-up window showed up:

"Your Channel got an upgrade!
We think you'll like what the new look has to offer you and your viewers."

Why would Youtube think I'll like the new look, if no one likes it? Everybody hates it. (Probably 80-90%.)

"you can always click "Edit Channel" and switch back to the old look"

Great. I would like to do that with the main page's look too. Then I could find videos and channels I'm subscribed to. Please change it back. That would be a great Christmas gift from Youtube/Google. Thank you.