My parents just weren't controlling like that. Granted, I'm a bit older than the average poster here I think (I was born in 1988), but even still... It just doesn't make sense for parents to stress over which video games their kids play. My parents didn't like the idea of violent video games so much, but they also didn't really keep track of what I was playing at all (it was mostly pretty friendly Nintendo stuff, but they wouldn't really have known if it wasn't). That was a wise road; me being able to experience media as I sought it out, including anything I might find on the completely uncensored internet, was important to me being able to grow into an adult capable of thinking for himself. I truly fear for every child who only experiences the world through the lens carefully crafted by his parents and not as it truly is...
Even if we move beyond the bad parenting style that is trying to control what your kids do, the ESRB still doesn't make any sense. There's no valid scientific evidence that violent video games cause any social ills at all, and it's not from a lack of looking. Despite the massive rise in prevalence of such games, violent crime is now the lowest that it has been in the entirety of human history. Some studies have shown that playing such games causes a slight increase in temporary aggressiveness (almost like playing an intense game gets your adreneline pumping), but no study has ever shown any detrimental long term effects whatsoever. If the evidence pretty universally fails to show that violence in video games causes any problems at all, why do we even need a concept of "mature" games? Very young children might find very violent games scary and hence wouldn't enjoy them, but beyond that, I really can't see any problems with kids of any age playing any games. It would be better if the ESRB did not exist.