Make your interviews difficult. The (right) candidates want you to.
As much as we may say otherwise, free and easy are not what we want when it comes to a job. We want to be challenged: to know that those we work with will push us to be our best.
How does this relate to interviewing? Simple: if you ask only light and fluffy questions, they will think you are a light and fluffy place to work. Even worse, they will think you (and by extension, the company) are an employer who will let just anyone in the door. If they come to work for you they can expect to have low expectations placed on them, limited or no useful direction or feedback, and have coworkers who aren’t very good at their jobs.
Not really the message you wanted to send, was it?
Instead, ask candidates tough questions. Make them dig deep, work on their feet, come up with novel approaches to challenging problems. They will thank you for it. They will think you are the kind of place they want to work. And since you pushed them to the breaking point and still offered them a job, perhaps they’ll do okay. After all, you know them better than any of the other yahoos who just asked them to walk you through your resume (yawn).
Cartoon thanks to Canary Pete