To be a great interviewer, you must get out of the habit of passively witnessing how somebody acts during an interview. That puts you back in the realm of voodoo hiring methods, where you end up basing your decision on how somebody acts during a few minutes of a certain day.
I'll admit to putting a lot of stock in how someone behaves and interacts during an interview, perhaps without putting the appropriate amount of attention into preparing questions and directing the candidate.
