You haven’t lived until you’ve fired a flintlock!
I've fired some lovely flintlocks over the years, especially a fantastic swivel breach that I swear I could hit the bullseye all day long due to how smooth the action was. The biggest shame is that there's so few beautiful pieces like that, and most of them are sitting in places of honor in collections, not where they really should be, in the hands of shooters on the range.
Alas, most people who have experiences with flintlocks will be with some pretty bad actions.