Every game needs rules, without them everyone would be playing a different game. You can’t pick up the ball with your hands in soccer (unless of course you are the goalie). That is a fundamental rule in soccer. If someone breaks it then they are no longer playing soccer the way it is meant to be played. If you hold a defensive lineman when he is trying to get passed you then you are breaking a rule of football. Once you do that you are also not playing the game how it is meant to be played.
In every professional sport there are hundreds, if not thousands of rules. There are rules about what players can do, wear, make in salary, when they can be traded, etc. Even though there are rules for almost everything, modern athletes and coaches find themselves adopting unwritten rules.
I think the best example of this is when you are up in a game and you take out your best players. I know it is partly because you don’t want to risk them getting hurt, but let’s not forget that it is also partially because you don’t want to humiliate the other team. It makes the coaches and organization look bad when you run up the score against a team when you don’t need to. Because these things coaches in most major sports have decided to take their star players out and put the back-ups in for the last couple of minutes of gameplay. You are not forced to do this, and some coaches choose not to (but they are the worst), but it is an unwritten rule and most coaches have accepted it.
There are some unwritten rules that don’t really benefit one team or another. When a coach takes out his best players he is doing it to look good, rest his players, and ease up on the opposition. Therefore, he benefits all teams. In hockey, there are unwritten rules about fighting. The rules are really only for self-preservation of each fighter, not necessarily for the whole team. If two players in hockey are fighting you never attack the double-team, head-hunt, or go on after the opposing player has had enough. When squaring up both players either leave the helmets on or take them off. All of these are unwritten rules and they in place to make sure each player has a fighting chance.
In basketball the taller players will usually guard the taller players, the fast players will guard the fast players, and the strong players will guard the strong players. I know that it doesn’t always end up that way, but usually you will see Tim Duncan guard Chris Bosh and Steph Curry guard Chris Paul. There is no rule saying that the forwards have to stick to the forwards, but that’s how it ends up happening. Mostly it happens because if Chris Bosh were to guard Steph Curry you would have a terrible match-up at both ends of the basketball court. Some might argue that it is more of a strategic play as opposed to an unwritten rule, but I would say it is both. You don’t want terrible match-ups, so you have similar players guard similar players. Sometimes, you will see a player guard someone who is far too big and he will get outplayed and humiliated. Coaches don’t want their players to be humiliated so they make sure they give them good match-ups. The coaches have an unwritten rule to make sure their players don’t get humiliated by guarding someone bigger, faster, or stronger. Sometimes it may happen, but coaches should put their best guy on the other teams best guy.
The unwritten rules shape the games we play. For the better of the game and sport coaches, players, and administrations have decided upon these rules and agreed upon these “rules”. They keep the games fair by eliminating some of the upper hands one team might have over another. They keep the games respectable by making sure coaches don’t run up the score. Lastly, they can keep the games safer by regulating how players can fight in hockey. These unwritten rules make our games better, not worse, and I would not be surprised to see several of them make their way into the actual rule