So I started playing Pokemon XD: Gale of Darkness (best pokemon game ever btw) in Dolphin some time ago and yesterday I took a break and I downloaded a bunch of other gamecube games to play, I started some of them and I accidentally pressed A when one game asked me Do you want to reset the memory card? I was really mad at me for not reading, but more so at the fact that I was about to beat the game. After that I just couldn´t start all over again, and not only with this game I have faced this situation before and I just can´t do it.

So what do you do in this type of situation, you start the game all over again or no?

Back in the day I had a GTA San Andreas save file, and I was very close to completing the story line. I got a PS Demo Disc from a Playstation magazine, loaded up one of the demos, but it crashed. I tried it a few more times, it didn't work, so I tried a few of the other demos on the disc, and they worked fine.

Turns out there was some issue with that particular game, and not only did the demo crash, but my entire memory card got wiped. I was.....pissed.

Started GTA SA from the beginning again, and ended up getting Gran Turismo 3 free from Sony as an apology.

EDIT: Found the story http://www.eurogamer.net/articles/news221104ps2demodiscusa (stupid Viewtiful Joe 2 demo *grumbles*)

EDIT 2: Ha read through those comments, the second one from the bottom is "Imagine if you had a GTA:SA save !!!!".  

This happened to me recently when I tried beating Twilight Princess for the third time. I just quit the game and didn't care all that much just because I had already beaten the game twice before.
This also happened when I was playing Persona 4 for the first time. I ended up just buying the PSVita version and replaying it a few months afterward. I was really annoyed at first, but now I'm kinda glad it happened because otherwise I probably wouldn't have gotten a PSVita and also this version is superior to the original in almost everyway.

Depends on length, fun, and whether I really want that resolution.

Is this a thing? It has never happened to me.

Sorta similar, but last year, I was trying to beat Link to the Past for the first time, and I was playing on the SNES. Got to the last dungeon (Turtle Rock) and a few days later when I came back to it, found out that the battery must have died and my save file was erased. Haven't gone back to it since. I like the game, but I've played the beginning portions of it so often, and the ice dungeon annoyed me so much, that I just don't really wanna try again to beat it yet.

It depends on how much you like the game. When I was first playing Wind Waker, I didn't have a memory card. I had to keep my console always on.

There was an outage.

I shrugged it off and played it again. Twice before I finally beat it for the first time.

Not very many games I'd do that for.

It depends if the game is worth it. If it is, I curse for like 20 minutes, pace angrily around the room, and retry hours later.

This also sounds like what I'd do. 

Depends on the game, you'll start over eventually but usually not immediately.

Oh and Colosseum is better than XD by the way (very underated opinion I know).