I’ve had a few. Most embarrassing was one of my first longer IFR flights. Bonanza, on a grey approach everything lined up great… touch down and the engine and prop stop! I’m like what is going on!? NO GEAR DOWN! Belly up on the runway. Ugh! I’ve done that more time than I care to admit. But that first time really gave me a jolt! Gotta remember GUMPFLS check (Gas, Undercarrige, Mix, Prop, Flaps, Lights, Speed and safety belts!)
Scariest situation I had wasn’t necessarily anything crazy, just too real and too close to home. Flying Cirrus SR22 on approach with a decent crosswind, everything looked great. Apparently I wasn’t hitting the correct v speed with the wind I was encountering. The left wing dipped. Stall, spin crash from about 300ft AGL. Nothing I could do but say “this is it.” This really was impactful because this happens all the time in GA. You think you have it all dialed in, then stall, spin, crash. I remember just staring at the damage to aircraft reload screen for the longest time.