Juice makes Breakout much more fun, and it will also make your game much more fun

in a parkour it's movement, in a sandbox it's creation, in a strategy it's strategy — adding a zillion features is not important to make a game fun, instead you must make the main thing that the player always does feel great

the rules of Juice are different for different types of games — calm games should have different effects than action games — but when done right it adds so much Life to a game, it just feels great to play ☺️

you — the developer — might already find your game fun without juice, but most normal players will stop playing the juiceless game before they find the fun. so you need juice to keep them playing the super easy intro of your game, only then will they play for long enough to find the real fun of the game.

pro tip: if you want to know more about Juice, you can also search for 'Game Feel'