I'm a bit far from my teenage years, but I have been working since I was 14. I remember being ecstatic when I turned 14 because it meant I could finally get a part-time job. I started out as an usher in a hole-in-the-wall movie theater. This job taught me one of my first fundamental life lessons: people are ****ing disgusting! Seriously. People will go through the trouble of ordering a cup of water so they have a place to spit the chewing tobacco they snuck in, and then, when the movie is over, they'll just throw the dam thing on the ground & let it get everywhere! And don't get me started about having to interrupt a middle-aged couple's coitus because I needed to sweep the aisles before the next show.
I've come a long way since then, and I largely regard that as a terrible job. But I will not deny that it taught me to value all workers, even those performing jobs that some might consider beneath them. To this day, I always make sure I neatly & properly dispose of my trash at public venues. I've been there, I know what hell those employees have to see, and I refuse to be part of the problem.
[I'll gloss over the part about how much I detested call-center work and move onto more interesting fare]
I've never shared the distaste for blue-collar workers that many seem to have. My dad was blue-collar his whole life, and he's the one who helped instill me with what I consider to be a pretty damn fine work ethic. He always pushed me to succeed in school, though. He said that he at least wanted me to have the choice to do something other than physical labor. After spending some of my college years paying tuition & rent by running network cable in "under-construction" office buildings, I can see why. But, as bad as that job was, it paved the way for my current career.
I'm currently an IT professional, and I love it. I do some physical labor (moving/installing new equipment), and I do a lot of mental labor (some of those off-the-wall issues can be a real pain troubleshoot). At the end of the day, I like my career, and I enjoy my work. I never forget the jobs I had leading up to this career, though.
I think a lot of kids today could really benefit from working. I'm not going to lie: the work is hard, and you won't make much money. But you will learn a lot about life, and you will learn some great everyday skills (Best Buy wanted to charge my brother $300 to send someone out to mount his new TV for him... I did it faster & better, and all I charged him was a double-cheeseburger combo meal). And those are the types of things that no one can take away form you.
-DW