Ready up in lobby screen.

[Lesterwormer 0]

In the lobby you can press Y, and if everybody is doing it the game starts up. But there are always players not readying up. I know a lot players would love it when the game starts up when for example the half  of the players are readying up. 

[Edmin Rossy 7]

I usually grab a cup of coffee ☕ before the game starts so I don't mind waiting.