I follow the JFK tower enough that I recognize maybe 5 of the voices, but Dennis was the only I had a name for. My recollection of him is that he took more care than anyone else working tower to explain to the traffic waiting hours for take-off clearance just what the problems were. He often had no better idea of when things would move than anyone else did, but at least he tried to make clear the problem(s). The guy had/has the patience of a saint, spoke slowly and carefully, and seems to care as much about minimizing flight crew aggravation as in just moving metal.
One of the best!