I've seen a few posts here and there about the worst GM, worst game session, worst player, etc. and it's inspired me to recount my own tale of woe. It was an easy choice—I've had exactly one really terrible game experience, run by "That Guy" I knew in college, and it almost singlehandedly turned me off to fantasy gaming for five years. Here it is:
At the time, our group (composed of high school students, college students, grad students, one professor) was taking turns in the GM's seat, running short arcs of various games. One week, a player I'll call "Steve" took the reins, promising to run his own homebrew fantasy setting which, in his words, had been under development for decades.
That should have tipped me off right there. Excessive pimping of your own setting and/or game system is often a harbinger of a bad game.
But anyway, we rolled up characters using our generic fantasy system of choice, met in a tavern and got our mission. We were to sail across a vast sea and perform some task. Exactly what it was didn't matter; we never got there. In fact, the session lasted about two hours before we all stomped away from the table in disgust. Read on:
Steve explained that wood was very rare in his campaign world, so all boats were carved out of stone and then made buoyant by magical enchantments. This, he explained, was very commonplace and enabled stone merchant ships to ply the seas of his fantasy realm. Good stuff—we boarded our rock sloop and set sail for the horizon. No doubt adventure awaited us in the wilderlands beyond!
At this point, about an hour of play time had elapsed. Another hour remained, although we didn't know it at the time.
After a day or two of sailing in our magical granite clipper, with no land in sight, we entered the first line of defense set up by the inhabitants of our destination.
It was an anti-magic aura.
We sailed right into it. And our boulder boat started sinking instantly.
This development prompted a huge metagame discussion about what, exactly, we could do to save ourselves. We brainstormed, strategized, dumped excess cargo, shed armor, tried to flee, argued with the DM—to no avail. He had a bemused expression on his face, like he was just waiting for us to stumble across the obvious solution to the problem, but clearly there was none.
After 30 minutes of this, we all threw up our hands. "We don't know what do do!" we moaned.
But Steve knew what we could do. And he told us.
"You all drown!" he crowed, rolling dice to see just how long it would take for our lungs to fill with saltwater and for our bodies to stop twitching spasmodically.
You could have heard a pin drop at the table. One by one we picked up our dice. A few guys went outside to smoke. A couple more went home immediately. The oldest player, whose basement we were playing in, tried to gently talk some sense into Steve and explain what a crappy game we'd just had.
But he didn't get it. In fact, the more he was taken to task for the impossible scenario he put us in, the more he dug his heels in and refused to compromise. He kept insisting that his world was awesome, that we'd agree with him if we just rolled up characters and played again. But at that point, the damage was done.
I didn't play fantasy RPGs for years after that, preferring instead to focus on sci-fi and superhero games—anything to avoid a game with freakin' magic.