Rule of Least Surprise says: anything ( some it system in our case) should behave in the way that causes the least surprise to people, users, us. We all love suprises we feel good about… not the biggest fans abotu those bad or negative experiences. Surprise creates confusion, bugs, and lost trust. Prefer predictability over cleverness. Think about it… when you call a function, you expect it to do what it says, not sneak in extra behavior. Silent mutations are a classic trap. Side effects are unknown to the user. Trust me, the user will NOT FIGURE IT OUT. Passing an object and having it changed behind your back. Magic…