Lets call him Mr. Module mc'Railroad. Mr. module learned how to GM from some very rigid and dry rule book somewhere, and seemed incapable of running an adventure that wasn't already written already.
Worse then that, his presentation was dry, with action and interaction (what little there was) delivered in the same dry monotone a crusty old history professor would use on his lecture to the class some lazy afternoon. (When not gaming he had plenty of personality, it just all bled away when he set down to game, as if he was transmogrified into a golem by the dice.
Even the combat was dull, a harrowing encounter with bandits (magical lightning bolts to disemboweling axe cleaves) described as calmly and serenely as the market place spices, or the evening meal at the inn.
The real frustration was whenever one of us tried to do something outside the narrow confines of the module we were instantly told "that's not in the script, do something different."
It got to the point during his games even the flies in the windows would cease buzzing, and be lulled into a stupor by his droning, never varying voice, like the dull hum of a fan on a hot summer day.
After about 6 sessions of this I stopped showing up, not so much because I was bored to tears, (although that did factor into it) but more because I had trouble staying awake on the hour drive home after playing in one of his adventures. The Best:
The best ever I'd have to say is Murometz, and his Hard Way campaign. (Yea I know pretend names for this, but I'm pretty sure Murometz isn't his real name
) From the cinematic quality of detail in the NPC cut scenes to the presentation of the entire story line, the game reads more like a best selling novel then a mere rpg.
It's a rare Gm that can keep a campaign moving at such a smooth pace with a solid blend of interaction, intrigue and action, while creating NPC's that have instant appeal, and seem to perfectly fit their roles without apparent effort.