Being an oldie, from a parent's point of view, yes I have kept myself from buying some games, and I won't let my kids buy any games that are rated significantly higher than their current age. So, no R16 games from my 12-year old, but R13 games are OK. I'll probably let him play R16s only once he's 16, or if I've played first and think the R16 elements are at the low end of the rating. Like Uncharted is R16, but I think it is borderline R13, so my kids can play it once they are 14 or 15.
No R18 games (GTA games are R18) in the house, period. Unless God of War III is an R18 in which case I'll convince the wife to make an exception. But for the most part I don't need R18 levels of violence, sex, drug use or whatever else puts a game over the top into the highest rating category for me to have fun with a game. When it gets to that level I find that it ends up detracting from the game rather than adding to it. I pretty much don't bother with R18 movies either, though there have been some good quality R18's I've seen, like Requiem for a Dream, a brutal but compelling movie.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
