Keeping details vague since you're not interested in spoilers.

Coming at a boss with a wrong strategy, getting hammered, and then finally getting back to get my stuff and.. the boss doesn't despawn! I've lost multiple armour sets, characters, and worlds to that boss because stuff this, start again. That boss was much easier last time, I'm not sure if I got better or it got nerfed - though I did come at it different.

My most painful death though is usually the latest, and in this case because it was embarrassing. Good food, good armour, high stats doing well just chilling out mining a thing - when out of nowhere a one star shows up. This thing hits hard, but I've taken on several at once before and come out fine, but mentally I was just not expecting combat. I miss all my parrys, half my hits, I'm backed into a corner (of my own making) getting staggered and running out of stam - but that's ok because my health was draining way faster than I realised and I was already dead. Slept where I respawned to clear night spawns and portaled back to my corpse 5m away. Could have been worse, that portal could have been destroyed.