Using a peter griffin term, what grinds my gears:
When TNT/phantom/retail doesn't tell you time on fireworks or info is not made available for cakes and such.
I have about 15 tnt cakes and no idea how much time they run for. I called the store, the corporate office, and even tried finding the plant info to call them and nothing. How is it that this information is not ANYWHERE
(Don't go into me about purchasing retail it was a decision made not by me but by the person paying, even with warning). Some of them had videos and i timed them, but most do not.