If you play tabletop games with friends or maybe even in a games group, you may have come across certain taboos. There are things that people don't like you doing. Some of these are to with ensuring that there is no cheating, others are about keeping a game in pristine condition, others are just some sort of personal house rules or traditions. Different people or groups will have different rules, and many will seem obvious or sensible, but others may feel unusual.
All games have some sort of rules - even if they are very basic or very fluid. Rules give a game the structure it needs so all players know what they need to do. Rules allow everyone to know what to expect from a game, even if the game includes a lot of randomness or unpredictability. Rules aim to prevent disagreements among players. Without rules there would probably be chaos - but then sometimes that is what you want from a game.
When creating a new tabletop game, a large chunk of time is spent on testing. Even very simple games need to be thoroughly tested to ensure they work. Playtesting helps identify whether a game is fun, balanced or swingy, lasts the right amount of time, works with the intended number of players and if there any issues with the rules.
If you have played a few tabletop games, you will have probably come across some that either don't quite fit your expectations or are a little ambiguous. That's where variants and house rules come in.
Every tabletop game comes with a rule book. Even the simplest game needs a basic set of rules. More complex games need longer rule books of course, but there comes a point at which a rule book becomes too long and turns people away from the game - and this point will be different for different people.
