Bad interviews can go both ways. In my opinion, the biggest contributing factor to a bad interview is underestimating its importance and formality.
For students, this simply means remembering your audience and your purpose. You are not talking to your frat brothers or family friends. In an effort to relate to or bond with your interviewer, you don't need to find common personal ground or use street slang. Instead, you want to be professional and prepared to talk about how you plan to contribute to the overall organization. You want to show that you are reliable and you will be a good fit for the company. That you are someone they could and should invest in. That you are committed to the company's purpose. That's not to say that you can't relax, be fun or easy-going. You want to show your personality too. But even if your interviewer does or says something unconventional, remember that your job is ultimately to impress whether you take or even want the job.
It's also important to remember that you are observing them as well through this process. The hiring manager is the face of the company. Ask yourself what kind of impression this person gives.
Recently, one of my students was super excited about a job interview but returned from the experience confused and disappointed. First, it was conducted in a bar during lunch time (the student was not 21). The company rep ordered a drink. She also had a gaggle of friends at the bar waiting for her to finish the interview so she could come join them. Her manner was flippant and a little too relaxed. The interview felt rushed and meaningless as the student couldn't join the party and felt like the rep was hurrying through it so she could get back to her friends.
Surprisingly, the student was offered the job. She declined because she got a weird vibe from the interview and felt that the offer had nothing to do with her specific talents--she was just a warm body. Then a VP called her into the office for an interview. The VP took the opposite tactic. She promised that the student would have a huge role in the operation and was ready to give the student whatever opportunity she wanted.
My student didn't know what to make of the experience. It seemed like a good job, but then it seemed like a job that was too big for her. Why were they ready to to promise her the world all of a sudden? I told her to trust her gut and keep interviewing at other places. The first interview seemed haphazard and disorganized and the last one seemed desperate. Neither were particularly professional or appealing.
In this particular case, the interview was a clear window into how the organization runs its business. But often times an interview will feel formulaic and removed. In that instance, it's important for both sides to push past the first impression. Before deciding on an offer, you can ask to meet with other employees at various levels. Ask tough questions. Ask about higher level operations and company vision. Come early for your interview, sit in the lobby and just observe. What is the company culture like? Is it obvious who's in charge? Is there an undercurrent of fear or respect? Are people busy or bored? Do people seem happy or engaged?
Use all of these inputs to make an assessment about whether or not the organization is right for you. Chances are, you will be there for at least a year which can feel like an eternity if it's not a good fit. Conversely, if it is a good fit, you can sink your teeth in and grow with a company that values your input. Going to work everyday can be an exciting challenge, not just a grind.