If you've just landed your first professional job--one that doesn't involve french fries--it's a big transition. The environment is very different from the university classroom.

Many companies have onboarding programs that will help acclimate you to the company, but here are the things you won't hear from your boss or the HR department.

1. Your manager can't fire you.

This doesn't mean you can't be fired, it just means that your manager most likely lacks the full power to fire you on the spot. If you're caught doing something horrendous, you'll be out the door by the end of the day, but otherwise, there will generally be a performance improvement plan and sign-offs on multiple levels before you are terminated. The bigger the company, the more likely this is. In a startup where your boss is the CEO, the process can be much faster.

2. Your manager can't give you a raise, either.

Your manager can recommend you for a raise, but unless there's money in the budget and no competing interests more valuable than you are, your manager can't just increase your salary because you've asked or even because you deserve it.

3. Even if you're a true superstar, you're not getting promoted for a while.

Lots of new grads come in with shiny diplomas and fancy awards and then get frustrated when they aren't suddenly the team lead or the manager. The reality is, there is a steep learning curve and you're at the very bottom. You may be doing great, but the chances of your getting promoted in less than a year or two are pretty slim. In fact, plan on being in that first job for two years. If you move up faster, great, but if you don't, it's not because you're not fabulous.

4. Your co-workers may be stuck in a seventh-grade mentality.

It would be totally awesome if everyone was mature at the office, but they aren't. You may end up located in a group of people who never got past junior high. Don't fall into their trap. They'll try to recruit you or attempt to shun you. Don't start being a mean person just to fit in with the mean girls. (And, yes, women tend toward this behavior more than men do.)

5. Your manager may not know how to manage, but give her credit.

Lots of people are thrust into management roles with very little training--especially people supervising entry-level employees. This means your boss may not know a great deal about her job and just might make mistakes. That said, listen to what she says. She was hired or promoted to this position because she had some awesome skills. Make every effort to learn whatever you can.

6. HR's job is to support the business, not advocate for you.

Yes, if you're being sexually harassed, go directly to HR. If you want some coaching or some advice, HR is there for you. If you just want to vent, try your mom. If you expect to go in and complain about your manager and have HR fix everything, you'll be sadly disappointed.

7. HR isn't bound by confidentiality rules.

Yes, HR should keep things confidential, but in some cases they absolutely cannot. If you make a complaint about racial discrimination, sexual harassment, or something else that is a violation of the law, HR cannot keep quiet. They are required to investigate. Additionally, while they should keep quiet about your medical problems, they aren't usually bound by the same confidentiality rules as doctor's offices.

8. Grunt work leads to success.

You had fabulous ideas of saving the world and instead you're editing documents, putting together PowerPoints, and responding to 150 email messages a day. No one is listening to your ideas. Well, that's OK. You need to do the hard work first, and people will recognize it. Volunteer for projects, and when you do, make sure you work really hard.

9. Flexibility has to be earned.

When you interviewed, the company said it had all sorts of fabulous benefits, such as flexible schedules. But if you start taking those benefits now, it might make you look bad, because you've earned nothing. Before you can come in late from time to time, you need to prove that you are capable, responsible, and hard working. So do the little things like coming in on time, filing your paperwork on time, and not complaining. When you've proven your worth, take advantage of those perks.

10. Admitting you are wrong is a powerful tool for success.

Instead of covering up your mistakes or denying that you did anything, say this: "I'm sorry. That's my fault. I'll fix it." Most people don't care that you made a mistake, but they will care if you don't fix it. Just let your boss know when there's a problem, and do your best to fix it. People will respect you when you take responsibility for your errors.