I think the previous generation tends to find fault with the newer generation--my parents did that with me--and their parents complained about them, when they were kids, and so on.
That being said, I understand your frustration with the kid, in this instance you outlined above. Yet, to take just one negative interaction with a stranger, and think that all (young teenage) kids assume most things are just disposable now, might be a bit of a stretch. Just my opinion I expressed here, but I've always tried to judge others on an individual basis, not so much on their age group.