Things that resemble state machines tend to produce reasonable interfaces when exposed in OOP fashion. The problem is more one of, you don't want everything to

Things that resemble state machines tend to produce reasonable interfaces when exposed in OOP fashion. The problem is more one of, you don't want everything to be a state machine, and adding the boilerplate tends to overcouple the data. The maximally composable form will tend to extract a little FSM with one variable, while all other relevant data is simply passed into every method.