When I was really young I remember when no one was home except for me I would be playing very violent games like GTA 3, Resident Evil,  Mortal Kombat etc all of which belonged to my older siblings  I remember feeling scared but also excited to play them I felt like they were "cooler" and deeper than other kiddy games that was easily accessible to me. 

Do you have any fond memories of playing M rated games as a kid?

Not really. The pressue never really got to me. First time I played an 'M' game was Left 4 Dead at a friend's house though.

Even as a kid I thought they were just stupid. I wasn't really a kid when games like GTA came around but, I was not impressed at all. I always liked more imaginative visuals and thought out places rather than some gritty generic real life place with blood and gore.
Just yawn..

Kinda I guess but not for long. Mortal Kombat was a big deal, I remember walking into a 7-11 during lunch break one day and seeing it and thinking "whoa". Also for whatever reason when (I think) Cid said "shit!" in Final Fantasy VII that was kinda cool, lol.

Generally speaking though the "blood is cool!" stuff kinda died down when Nintendo opted to allow blood in Mortal Kombat 2. That whole thing became a bigger issue when Nintendo denied it.

The first time I saw Grand Theft Auto (on PC) I remember thinking that was overboard. 

lol yes!
I remember getting Sims 2 and that Fantastic 4 game on my PS2 xD

No, I didn't even play M-rated games when I was little because I didn't find those games really interesting (shooters, gore, horror, etc. )

Still don't really care for most of them in fact, but I'm not against a game getting an M rating

Kind of, but only because being "M" sometimes meant the game was a lot more imaginative than the generic and shallow stuff that hit the "E" register in those days. Mortal Kombat, for instance, had an interesting premise, especially compared to vapid mascot characters running through the bare-bones shell of a story. Something deep and immersive like Silent Hill was mesmerizing in comparison.

Relative to GTA, though, I tried it and became completely bored with it in the same day.

I found all games pretty cool since my mom didn't let me play them until I was old enough anyway.

When I was a kid there was no rating system on games even tho some of them were much more explicit in nature than anything we have on the market now. Rape a woman in Custards Revenge. Sneak in women's showers in Porky's and um ejac in womens mouths with Beat em & Eat Em. Plus others. Did I think those games were cooler? No. No I did not and I still don't. I think a game is cool when I just think a game is cool because I enjoy it.

Not really, I mean I played Conker, GTA, Mortal Combat etc. but I didn't find them any cooler than Mario, Zelda, NBA, Crash etc.

Also of all the games listed Zelda (specifically OoT) is the one I'd least want a child playing because that shit despite its E rating was nightmare fuel for kids.