It seems to me that you are confusing two terms that have a very different meaning: maturity and age. And those are, AFAIK, very different terms. Also, you're making a relation between lazyness (the bad one) and arrogance and short age, and I must disagree with this assumption. I'm my short carrer, the more lazy and arrogant people I've met were usually around the doble of my age (22), whereas young people were those who had illusion and respect to the "more experienced" (notice the adjective, I'm not talking about older people). Maybe it's different in other places, maybe I'm too young to see things in your way, or maybe I'm totally wrong, but I'm a little tired of hear people talking about *young* people in a *disparaging* way. It's possible that some we, as less experienced, make some stupid questions, and maybe we have arrogance, but no more than older people in my opinion.

Sorry if I'm missunderstanding your words, but I've been too many times in situations where my age have played against me, and I think those assumptions take to wrong actitudes (young people->worse posts->worse work->irresponsability...).