Palidor12: Lots.
PS3:
- Final Fantasy XIII and XIII-2. I bought the second before playing the first, so I had no idea they sucked so bad.
- Demon's Souls and Dark Souls. Just not my cup of tea.
- Game of Thrones (the first game, not the Telltale ones). Big. piece. of. crap.
- Tales of Xillia 2. A silent protagonist... really? Not to mention an annoying debt repayment system, complete recycling of just about everything from Xillia 1, and the Allium Orb system is annoying. I'm playing it right now but I feel like shelving it permanently.
PC:
- Geneforge 1-5, and Avernum 1-6. Not what I was expecting. I did try to play them, but even after sinking in a lot of hours, I did not enjoy these games.
- I Have No Mouth and I Must Scream. Not fun and the story was dumb.
- Sanitarium. Just awful. It was not scary at all and the chapters had no connection to each other. It was like each chapter was made by a different person and then mashed together to create a game.
- Fable. It was a chore to finish this.
- Anachronox. It might be a good game, but no matter how I fiddle with the camera, I get horrible motion sickness after a few minutes of playing.
- Neverwinter Nights 2. What they heck did they do to my beloved Neverwinter? I loved the original NWN, but the sequel sucks rocks. Besides the shoddy camera and unfriendly interface, the story was totally uninspiring and the companions who joined you were thoroughly unlikable.
Wow... judging by your post, we have the exact opposite taste in games! Apart from Final Fantasy XIII, XIII-2 and perhaps Game of Thrones (depending if you're talking about the RPG or strategy one)... almost all the rest on your list of regrets fall into my personal list of "all-time favourite games". Weird. :-P
I especially love Avernum, Geneforge, Sanitarium, Fable (such fond teenage memories of the original), I Have No Mouth and I Must Scream and Anachronox (that atmosphere!). I prefer the first Neverwinter Nights to the second one, but don't regret purchasing the second one. Demon's Souls was a game I got before Dark Souls became a hit *insert smug hipster smilie* and I did hate it at first... but then it grew on me. Eventually I ended up loving the whole series.
My biggest game regrets? Too many to speak of. Some terrible adventure games like the Ankh series come to mind. Also; FORCED and Krater. I bought both as co-op games to play with my partner... but they were too broken to play.
I admit that FFXIII was seriously disappointing. >_<