Indeed, the learning process is important. I think it's particularly instructive to look at how `ap` is implemented, and what is left out in the transition from Monad to Applicative:

    mf `ap` ma = do
       f <- mf
       a <- ma
       return (f a)

With a Monad, the action on the right of the bind operator is a function of the result of the action on the left. The second operand of the `ap` function, however, does not have any access to the result of the first operand. The two operands are evaluated independently, apart from their side-effects. That reflects the fundamental difference between Applicative and Monad: an Applicative instance just sequences effects and combines results, whereas a Monad instance allows effects to depend on previous results.