OO is pretty simple. Use objects. There are many many patterns that you can use that rely on this concept. You don't need to use every pattern to be using OO

OO is pretty simple. Use objects. There are many many patterns that you can use that rely on this concept. You don't need to use every pattern to be using OO. Even at the most basic level of "a scoped namespace", OO can be useful in organization. The fact it can be used in many ways means there are many perspectives on how it can or should be used. Popular OO languages are also very pragmatic. That means that even if they are OO languages, they allow for non-OO patterns as well. OO is flexible in this way. A counter example is FP, where it is not very flexible. FP has many rules you must follow to make the concept work, such as how mutability is handled.