They taught us this in Boy Scouts. My dad, a doctor, was always angry whenever this was pushed though. It may help someone mentally if they are hyperventilating from an anxiety attack, but it can cause harm in numerous other situations like if a person is having a heart attack or an asthma attack. A doctor or EMT would likely never have a patient breath into a paper bag.

Get rid of offsides. It slows the game down and is hard for most observers to understand. It’s also stupid.

Punish fake injuries and possibly get rid of personal fouls. Have a penalty box like hockey. Maybe only allow players to kick each other.

Make legitimate close shots on the goal result in a corner kick instead of turning the ball over to the goalie. This way players are rewarded for taking risky shots. And a missed shot doesn’t result in the game’s momentum halting to a stop. It’ll result in more goals and make plays happen more often.