Microtransactions don't work exactly like this in NBA 2K14, but this parody video by GoodGameBro clearly communicates how ridiculous some find the practice when it intrudes on their favorite sports game. Actually, you can purchase dunks, they're just signature animations for your created MyPlayer.
This whole micro transaction business is a bit disappointing in this very early generation. In order to get the full experiences of Killer Instinct, Battlefield 4, and Forza 5 I had to put in significant amounts of money for season passes and DLC. Then an idea popped into my head. Why not develop a system where you can demo the DLC (say a bonus character) with strings attached (say a 24 hour expiration).
I know companies don't "need" to do this and probably won't but it would be nice to see if shelling out say 20 dollars for a car in Forza is worth it before actually pulling the trigger. Might help build brand support and serve as an important feature when people are contemplating a console purchase as well.
Now for the corny late night punchline: "Imagine how many people wouldn't own horse armor right now if this existed!" *cymbals*