I hear from a lot of twenty-somethings about their horrible bosses. Been there, done that! I don't work for myself for nothin', after all. However, as someone who has sat on both the employee and employer sides of the table, it occurs to me that a lot of those complaints are really just reflections of their own inexperience in the workplace.
I've written previously about the Devil Wears Prada phenomenon. Here's some more advice to consider as you deal with tricky bosses.
1. Your boss is not your friend, let alone your BFF.
Today's crop of twenty-somethings has a hard time with that distinction, and you can avoid a lot of misunderstandings and grief on your first job if you treat your boss like your boss. She probably doesn't care what you did over the weekend, and she's not interested in hearing how bad the traffic was on the way to work. It's one thing if she asks, and another thing to volunteer that information.
She also doesn't want you to behave as if your workspace were your bedroom, with your music playing and your friends IM'ing you every ten seconds. Don't force your boss into the role of your mom. A lot of first-time employees who think their bosses are "mean" just haven't adapted to the professional world yet.
2. The mean/friendly axis isn't the only one that matters.
Professionally, you're better off with a mean boss who is great at what she does, can teach you the ropes, and will open doors for you than a friendly boss who is never going to get anywhere herself. It can be unpleasant to work for a boss who is curt and impatient, but that's life.
There will be plenty more bosses -- and clients and colleagues and business partners -- whose social skills you don't admire, but whom you need to cultivate for one reason or another. It's a good skill to be able to separate in your head whether this person is helpful to you professionally and whether this is someone you'd want to hang out with socially.
3. Your boss's actions or behavior might seem completely irrational to you, but she probably has good reasons that just aren't transparent to you.
It would be great if she could explain to you her motivations for every single thing she does or doesn't do, but she likely doesn't have time to do that, and you have to learn to roll with that. Once you're in her position, you too will be doing things that your underlings find stupid or bizarre or unjustified, simply because they don't have the big picture about the project or the department or the industry that you do.