Folding stock shotguns, pistol brace shotguns with slugs, 12 gauge magnum shells, and high velocity 12 ga slugs. They have their time and place. But they're not a whole lot of fun for me.
Single shot firearms in general are tedious for me. There is value in forcing yourself to slow down so you actually focus on the shot and build your marksmanship skill. But a bolt action is more than enough to do that for me. For that reason I do not enjoy muzzle loaders, except actual historical guns or exact reproductions, which I enjoy putting 1-2 shots through for the novelty, and that's enough.
I don't like shooting guns that are unreliable under ideal circumstances. Anything that will fail to feed, fail to chamber, fail to extract, fail to eject, etc when properly cleaned, properly oiled, using the proper ammo... I'll just get annoyed. Looking at you, TEC-9.
I guess I sound a little picky compared to most of you, LOL
A few years back I got the chance to shoot my friends S & W scandium 357. After one cylinder never touched it again!