Left one is better.
It started as a joke about socks. It is still the best explanation of the line.
Two socks, one review each. "Left one is better." on the left. "Right one is better." on the right. It was the first joke in the first line, and it never left.
In this storyLeft One Is Better. SocksPaper.$10
Why it stayed.
It is the whole idea in one pair. A review is an opinion, and opinions come in pairs. Wear them, and you have settled nothing at all.
People tend to buy them for someone else. The best review is usually the one you hand on.
Where it went next.
The joke moved to the pickleball set: two paddles, one opinion each. The socks are still in the line.
In this storyLeft One Is Better. Pickleball SetPaper face.$57