Projection time: You ever come out of a movie fuming and gnashing your teeth, and when your pal asks you what gives, you groan, "God, what a wasted opportunity!" and then spend your walk back to the parking lot (and a good stretch of the ride home) iterating a laundry list of ways the film could have been oh so much better?
I will let you briefly cast your minds adrift and recall any such recent letdowns. For some, it was Man of Steel; for others, it was Pacific Rim; for me, it was both New Trek films. Your money and mileage will vary. (MoS and PR were fine movies, if also flawed in endearing and stimluating ways.)
Now, I say "projection time" not because of the gizmo at the back of the theater, but because a) I've done this sort of Gedankenexperiment more times than I can count (no, really, now?) and b) I'm just dumb enough to assume most everyone else with two hemispheres to bang together does it also. It's not bad movies, or books, or records, or what have you, that drive me this bonko; it's wasted ones. A great concept, a memorable setting, a striking character — those things can all be easily profaned with the most unworthy hands.
But the whole concept of waste is is subjective, and that's why talking about it as a general aesthetic issue is such a man-trap.
More people than I can count have groused about how many things I liked and appreciated were complete wastes of an opportunity, only because they didn't get what they wanted. So how do you tease apart your own little what-you-want and set it aside from the rest of the whole pizza pie of what-would-be-best?
It's bad form to criticize something for not being what it was never intended to be, but we easily confuse where one begins and the other ends. No one complains about a piece of bubble gum not being a very good steak, but only because the differences between the two are so self-evident. Where, though, does a good action romp (e.g., The Fast and The Furious 1-2-3-4-5-6-etc.) leave off, and a bad science fiction movie (Star Trek Into Darkness) pick up, especially an era of increasingly blurry genre and target-market lines? I suspect I'm not courting much of a beating if I say the worst of the first franchise is still better than the best of the second, if only because the fresh bubblegum of the former beats the alternately underdone and burnt-black steak of the latter.
Here's my operating hypothesis: A wasted opportunity is about more than just having your tastes failed. It's when the people in charge owed something to the audience they were trying to reach, but didn't bother to live up to that. In short, every wasted opportunity is best appreciated as a shirked creative responsibility. They could have done something, but they chose not to. They took the easy road out. That's a chance for you to learn something from their mistakes.