Regardless of the trade or profession, you usually know when you meet true professionals. They are completely at ease in their environment; they act in a way that seems natural and appropriate; and they exude a quiet confidence.
Lawyers are no different, and the professionalism they exhibit should instill a sense of trust in their abilities and judgment. They should be polished and personable, and proud of their accomplishments, but not arrogant or condescending. Their questions should be directed to making you feel at ease, yet thorough enough to convey the sense that they are deadly serious when it comes to your legal business, and will be leaving nothing to chance.
Above all, they should be more interested in finding a sensible solution to your particular problem than in finding someone to blame for it.