If you're a decent regulator, it's your job to be a cold. That's basically the whole point. You don't need to be an asshole, but you should damn well insist on deference and distance.

By way of analogy, can you imagine a judge dispensing with formalities and telling the people facing him in court "Relax! Call me Jim." Obviously not. Because when it comes to the law, conspicuously arms-lengths relationships are essential.