All major sports have voluminous sets of rules. The NFL perhaps has the longest — topping out at 318 pages. Baseball, America’s game for the past 150 years, has some of the most detailed and aberrant rules, no doubt written in response to cheats, loopholes, exploitation, and a long history of weird situations.
But, just as there are forests worth of rule books out there, the unspoken etiquette of games could fill even larger volumes — “the unwritten rules.” Every sport has them. And, how you feel about the unwritten rules will probably depend on your view of sportsmanship and/or how superstitious you are.