I once made a classic steak au poivre for a dinner party. I used pre-ground pepper because I was in a hurry. The crust was dusty and bitter, not crusty and bright. It was like watching a sad, tired raincloud instead of a thunderstorm.
Next time, I cracked a dozen peppercorns with the bottom of a heavy pan. The difference was night and day. The pepper was floral and sharp, and it actually made my eyes water in a good way. My friends asked what “fancy spice” I used. I just laughed and said, “A peppercorn grinder.”