Fame
The professional opera singer is one of those artistic professions that oozes the ideals of the American Dream™. There's the slight possibility that your love of music and incredible pipes will propel you to the highest heights of superstardom. This applies mostly to you performers out there—composers haven't really been famous since the days before electricity. You can thank the rise of the talkin' picture shows for that.
Thankfully, for all you professional loudmouths out there, operatic fame is still possible, and occasionally better than other kinds of fame. This isn't Hollywood-style fame where you might be able to make it big based solely on how good you look in your underwear. No one is going to care how good you look when they're sitting way up in the second balcony. What matters is how good you sound when your bombastic voice reaches their tiny, distant ear drums.
Sure, many pros recommend staying fit so that you can work long hours and move around the stage. Jumping jacks are good for your health, and those costumes are so darned heavy that you might consider taking up weight lifting just to hoist your wig onto your head. However, your job is to move the adoring crowds to tears on their feet—and that depends completely on how you sound, not on what you look like.
To become a truly famous opera singer, you have to have the talent. The reason you've heard of singers like Luciano Pavarotti and Charlotte Church is because their voices are distinct, enjoyable, and intense. They don't just fill the seats with bums; they fill the rafters with their heavenly librettos and resonant melodies. They also worked and rehearsed until they were capable of vocal movements that few others can achieve. If you think school is for fools, fame is probably the least of your worries.
Being world-wide superstars, they also have great managers and publicists to do the gig-booking and interview-scheduling work, plus a team of rehearsal professionals to practice, practice, practice. When you first start out, you're probably not going to have any of that. As the saying goes, the best salesperson of your talent is yourself. So get out there and sell yourself (artistically-speaking).
Finally, remember this is a very public career, Shmoopers. If you're lucky enough to be one of the famous ones, be aware of what you do and say. Don't forget the age-old wisdom: the bigger they are, the harder they fall.