I do like my job and hope to have it for some time.
Better prediction is not the issue most of the time. We know what sells, but the process is more difficult than getting a dozen cheeseburger under the heat lamp before the lunch rush. It's a balance between what things we know will sell, what things production can handle based on the current workload in the various departments, and what raw materials are reasonably accessible at any given time.
Think of it this way:
Boss: I need a dozen Quarter Pounders with Cheese.
Production: Can't do it. Cheese is not accessible right now.
Boss: OK, give me six Quarter Pounders without cheese.
Production: OK, but we've already got twenty of those under way. You sure you want more?
Boss: Hmm. Probably not. What about Filet o' Fish?
Production: We can do those, but we're low on tartar sauce.
Boss: OK. Make as many as you can until the tartar sauce runs out.
Production: Oh...wait....we have cheese now.
Boss: Great! Give me those dozen Quarter Pounders with Cheese now!
Production: Ooops, can't. We just used the last of the buns on those Filet o' Fish, and the fry cook called in sick today.