"If someone seems like a jerk, they probably are. "

"In the tech industry, it is extremely common for interviewers to ask the candidate to solve a programming exercise. I find that this is an excellent opportunity to watch for signs of arrogance, as the exercise almost never goes well if the candidate fails to ask appropriate amounts of questions and demonstrate a collaborative attitude."

Reminds me of the words of Maya Angelou:

When someone shows you who they are, believe them the first time. 

So interviewer's job is to create an environment where a candidate can show who they really are :)

That's right!