Hardest Xbox 360 Achievement that you have accomplished

Whats the hardest Acievement that you have done, i dont wanna hear ohh getting number #1 on Graw leaderboards is hard, because chances are you didnt do it. If you did props. It doesnt have to be like really hard like mabey you had a bad experience with it such as you deleted your game save or something and had to do it all over again. I have a few

Id say the one hardest for me was mabey saving all the little sister in Bioshock, it was a somewhat annoying to kill the big dady but when i picked up the little sister i SOOOO wanted to harvest/kill her. So tempting but i did it.

Another was completing the mages guild quest in Oblivion. I Wanted to make a mage character to do the mages guild with, but i wanted him to be a high level, so i trained him up to level 15-20 or something and completed all the mages guild recomendations which i hated soooo much. and then i noticed that i had saved wayyyy to many times, and it i had to scroll and scroll just to get to my save to load it up, over 500 save files, i just did a new save after everything important dont ask why. and while clearing up my saves i deleted my character. Now since i saved my files after everything important i still had that character, but the only save i didnt delete was the one where he just started the recomendations and it took me 2 months before i was ready, and done being pissed to finshed the quests.

Another gay one was after completing all the levels on veteran diff of call of duty 2 i did not get the achievement for completing the game on veteran, i still only have 800 points in it and got to fed up to beat it again so i traded it in at gamestop

Well enough about my gaming experiences what are yours?

Id say the one hardest for me was mabey saving all the little sister in Bioshock, it was a somewhat annoying to kill the big dady but when i picked up the little sister i SOOOO wanted to harvest/kill her. So tempting but i did it.Aidan00000