Are you willing to admit you are wrong or don't know something? If so, how readily?
This is one of the single biggest things I look for when interviewing. I don't expect everyone to know everything, no one can. But someone who will fake knowing something and try to bullshit you will only lead to disaster later. If I am liking a candidate, and things are going well, I'll eventually toss in a question or two that I don't expect them to be able to answer. If you tell me you don't know, we're good. Tell me you dont know and ask me what the answer is, we're better. Bullshit me and I'll give you a chance to back out of it. Keep bullshitting me after the lifeline, and it's pretty much over right there. You'd be amazed how many people will bullshit. Last round of interviews, one candidate was doing awesome, and was becoming my favorite for the job until we hit this point. After the initial failure, I told him, it was okay, I know it wasn't on his resume and I didn't expect him to know it, and it wasn't critical to the job, I was just seeing if he had any experience in it. He then continued to make stuff up for several minutes until I finally cut him off. I don't care how good you are, if you haven't mastered "I don't know," you're pretty much worthless to me. I've seen the damage that crap can do, and I don't need it.