I agree with you wholeheartedly, being an overzealous 0L myself and knowing many 0Ls that act just as you've described. However, I would break overzealous 0Ls down into two categories: those with considerable life/work experience and those straight from undergrad with none. I feel it is primarily the latter that come in with unrealistic expectations.
I am a member of the former group, knowing that jobs you really enjoy doing are very rare. All I'm asking for is an interesting occupation and a comfortable middle class living at worst. Too many students imho enter law school never having worked a *&^% job in their lives. *&^% jobs build character and nurture a valuable cynicism in life, keeping you aware of the possible negative side to things.
I like how Professor Dershowitz welcomes his Crim Law 1Ls every year: "Statistically, it is likely that more of you will become criminal defendants than criminal defense lawyers."
More people straight out of undergrad have unrealistic expectations, but I wouldn't say it's "primarily" those people. Lots and lots of people who have a ton of life experience came to my law school with unrealistic expectations about how hard it would be, how it would change them, what it would be like, etc. Sure, having worked a job may make you understand how much worse off you could be, but I don't think it prevents people from expecting too much. For all the "silver spoon" kids, there are a sizeable number of non-traditionals who expect law school and a legal career to instantly give them the respect, admiration and envy of everyone around them.
A lot of them also have unrealistic expectations about what being back in school will be like. Some expect law school to be a lot more serious than it is, and are disgusted when people act like high school and college students. Others expect it to be a lot more immature than it really is, and are shocked when people aren't procrastinating and drinking all the time.
As far as the OP's question, remember where you are. I know a few people on this board say "I hate law school." I know a few say law school was a mistake. But remember where you are. You're on a message board, where it's easy to whine and moan, and a lot harder to express joy and happiness. It's really easy to come to a message board when you're behind in your reading assignments, you don't want to work on your memo, you're frustrated and tired, and you want to procrastinate. It's harder when you're ahead of your work, you're finding it very interesting, and you keep working because you enjoy what you're doing.
I know many psychological studies say that lawyers and law students suffer from higher rates of depression than the general public, higher rates of stress-related illness, and higher rates of alcoholism. Those are credible resources to find out about the negatives of law school and the legal industry. LSD is not.
Don't let this place change your expectations of law school. I think a lot of people have done that. Between a sizeable minority of posters here and the vast majority of XOXO posters, it's very easy to conclude that law school not only ends up being miserable, but that it's
supposed to be miserable, and that if you are happy, rested, and well-fed at any point for at least two if not all three years, then you are doing something wrong or not working hard enough. Law school is what you make it. You say there's a lot of people you would ask why they just don't quit, and I would ask why some of these 0Ls are subjecting themselves to an experience that they expect to hate in the first place. Most of the "realistic" 0Ls you'll find here are actually pessimistic.