Dark Souls. I rage quit when the butterfly looking boss killed me when I had a spare 17000 souls and 8 humanity. I can still get it back but as I have barely any magic resistance that thing just destroys me.
When I got 100% Cliffs of Dover on expert (Guitar Hero 3). I have the scars to prove it (I literally cannot play Guitar Hero anymore). And the term Epic Win is dumb as hell.
Edit: I thought I should clarify. On the run where I achieved 100% everything went well, I was so happy I had finally done it, but I then realised what had happened. My pinky had completely locked up, so instinctivlely I used my other hand to move it. It was a sharp quick pain and my pinky has never been the same. Now whenever I straighten my pinky it locks in place and I have to conciously focus on moving it back to normal.
Stealth games are weird. Splinter Cell: Conviction is the most fun I've had with a stealth game, take that how you will (I really liked conviction). I also played both Crysis games like stealth games. I had a good time but often found myself avoiding most large encounters with enemies and felt like I was doing the game wrong for most of it (I was missing most enemy encounters). But surely invisibility was included in both games because stealth was supposed to be a core gameplay mechanic. What I'm getting at is that for a lot of people they don't feel like they are playing stealth games right and that's what people find off putting.