Have you ever played a game right up to the very end before stopping entirely? Not just completing the game, watching the credits roll, and sitting in self-satisfaction (as if you actually accomplished something of value). No, after the days and weeks you spent - hours upon hours - working through a game, and completing 95% of it, you put down the controller and walk away, never to return.

Game Arrest Syndrome (GAS) is the onset of ambivalence that occurs from either A) overdosing on a particular game or B) intense frustration over a particularly challenging portion of the game. In its worst form you might be in the middle of attacking the final boss and turn off the console. Forever. This is called Sudden GAS (SGAS), and has happened on a number of occassions:
:: Metroid Prime - I blew through most of the game and even defeated Meta Ridley, only to encounter Metroid Prime. When I got to it, I tried to defeat it twice, looked up the solution on GameFaqs, and put down the controller forever. For some reason, I was just done.
:: Ninja Gaiden - After traversing multiple levels, timing my jumps just right, and avoiding the malicious (and abundant) birds, I reached the final boss of one of the most difficult NES games ever. Then I stopped playing for no particular reason.

:: Pikmin 2 - I spent a lot of time completing every single nook and cranny of this game, arrived at the last boss at the last level of the game, and stopped playing. I had no urge to pick it up again except to play with my spouse in cooperative mode a few times. I had already completed Pikmin, and had no desire to defeat the boss of Pikmin 2.
:: Unreal Tournament - I fought through every bot without cheating until I reached Xan, kept getting blown off the spaceship that you duel upon, and gave up. I cheated to complete the game, and never once regretted it, until just now when I told you.

Not just me
I thought that it was me that was admitting defeat all the time, but it turns out this is not the case. My wife is notorious for picking up a game and playing like crazy, only to put it down seemingly overnight. In fact, we both gave up on the following:
:: Grim Fandango - We each played Grim Fandango separately, loving every minute of its unique atmosphere and quirky humor. We both considered ourselves proficient adventure gamers, having been through King's Quest VI and a few others, but gave up in the middle of Grim Fandango. For some reason, with this game both of us would rather have given up than cheat to move on. This was sad, because we both so loved Manny.

:: Harvest Moon - Harvest Moon is a very long game. It is not difficult, but after a while it really began to feel like work. I made it through only one season. My wife made it to the end of the second season (of three), but gave up mid-way through because there was no challenge, she was already cranking out tons of cash and had trees planted everywhere. She owned everything worth having.
:: Twilight Princess - After hitting the Sky Cannon Glitch, my wife lost a lot of the energy she had put into Twilight Princess. I have not really started playing yet myself, but I can hardly blame her. She lost a lot of the bugs she had collected, some heart pieces, and other side-quest extras. For some reason her not completing this game bothers me, possibly because she completed all the Zeldas since Ocarina of Time without much difficulty. I'm still rooting for her.

You're not defeated, just out of GAS
I love video games, but they are just games, after all. I gave up throwing the controller across the room long ago. Today, I just put it down and never pick it up again. I complete many games, but sometimes, if I have had my fill, I get an attack of Sudden GAS and never return to what was once great fun. Do not feel bad for me, there are plenty of other games to keep me distracted.