Ever have that guy int the team that just didn't think things all the way through.

I was once playing a D20 Modern Campaign with my weekly group. We had broken into a library that was taken over by a team of terrorists. Our Dm thought it was a good idea to equip our Techie explosive bolts for his crossbow (I should note that the Terrorists were wearing explosive vests) We get into the basement of the building where the President was tied to a chair with an explosive strapped to his chests surrounded by 4 terrorists.

Techie- I want to shoot the guy in the middle with my crossbow.
DM- Okay, make a roll.
*Rolls natural 20 and confirms crit*
The DM goes on to tell us how the entire cluster of people in the middle of the room go up in a big explosion, and the floor of the floor above cave in on them.
DM- You know, I imagined that encounter lasting a lot longer than it did.
Soldier to the DM- You do realize that he just shot the president in the face.
DM- No he didn.... Oh sweet God.

Hahahahah! that one is pretty brilliant.

Awesome. I had a guy who thought it was a good idea to inform his local shamans (they're a nomadic tribe) that one of their newfound allies was involved with demon magic.

Said ally was already under suspicion from these xenophobic nomads. Moreso because she was a sorceress and they weren't fond of arcane magic in the first place.

Violence ensued.

This was not the player's goal.

What was the player's goal?
More importantly, why wasn't said player's goal violence?

Shame on the DM for not noticing, I say.

I had a player in a Palladium fantasy campaign that had gone on for years. We were well into the extra-dimensional phase of the game, and he was trying to find this spider queen that was made of phase material that could phase in and out like a teleport, but more importantly couldn't be hit in this time. This was the BBEG of this particular leg of the adventure.

The Character had just received a powerful item that was the equivalent of vorpal (a halberd) in function. Had a haste spell on when he rounded the corner due to him full on assaulting the spider hive...

I didn't even get to use my boxed text dialog I prepared. Natural 20 confirmed on the neck, severed the head. He grabbed the trinket he came for an left. It was a sad day for the GM. All the plot and story I prepared, straight out the window

This isn't a "bad decision" story, but I felt the desire to share anyway. This story explains why I hate fumble rules.

The first time I ever played with fumble rules was my second time playing D&D 3.5, 7 1/2 years ago. I was playing a cleric in "the world's largest dungeon," with two other players. I don't really remember a lot of it, but I do remember at one point we were fighting a displacer beast.

See, I had just healed one of my teammates, and without anything else to do, decided to wade into melee and whack the creature in the head with my mace. Unfortunately, the dice gods were not with me that day, because I rolled a 1. Playing with fumble rules, my GM said "roll again to see how badly you missed." So, I toss the die on the table, and after it bounces haphazardly on the smooth surface, it spins and finally settles... another 1.

At this point, I know something bad is going to happen, and I wait for a ruling from the GM. He takes a few seconds before telling me, "Your swing goes wide, hitting your teammate standing next to you. Roll one more time to see how badly you hit him." Still new to the game, I hadn't as of yet developed any dice rituals, and maybe that's what sealed my fate that day. After juggling the D20 between my hands a couple times, I tossed it on the table, where it bounced around, nearly rolling of the table. Finally, stopping precariously on the edge, the result on the die made my heart sink. I'd rolled a 20.

The GM chuckled at my misfortune. "Well, it seems what happened is that as you swung your mace as hard as you could, the head you were targeting disappeared. The force of your swing hitting nothing but air threw you off balance, causing your weapon to continue its momentum right into the skull of your adjacent ally. Roll for damage." And wouldn't you know it, that little D8 decided to roll for maximum damage. All the players at the table let out a simultaneous groan as we calculated the damage against the character's remaining hitpoints. The hitpoints I'd just restored back to him last round.

Minus Eleven.

Congratulations, Jason, you've just killed your own teammate. Here's your Worst.Healer.Ever award!!