Hm... I was running Dead Gods, with my usual group including a friend we'll call Dave and a newcomer we'll call Fred, invited by Dave. Everyone else save me and Dave found Fred annoying and wanted to get rid of him. Even I must admit he was fairly dull, but I wanted to give him time to settle. Still, there were some negative waves floating around even if everyone was as polite as usual. You know, body language and all of that.
So the second session with him the party arrives to an ominous dark temple in an otherwise blasted world. The temple is a powerful illusion, so powerful in fact that anyone entering it will die, no save, no if, no but. The players are supposed to figure out that it is an illusion, while staying well away from it before. To give them all the clues I can, I describe in details the waves of ungodly evil that emanate from the temple, so powerful that they stun you just by looking, and the insane drum music that comes from within, yadda yadda, and the feeling of sickness that comes from getting too close. A hidden fiend tries to Dominate a couple PCs to make them enter the temple with little success (the other PCs stop them). There are (illusionary) dark cultists that beckon the PCs to enter. So basically they have been told in twelve languages that they shouldn't enter.
Well, Fred gets dominated and begins walking towards the temple entrance. Dave however is the only PC close enough to stop him. Instead, he chooses to follow him, while the rest of the group, too far to act, mumbles that it doesn't look like a good idea. Since I somehow felt at a subconscious level what was going to happen (though I didn't completely realize it), I did everything I could to convince Dave to stop. I described with even more power the sheer evil and pain emanating from the entrance, and the complete, utter devouring darkness within, and I prolonged the two rounds it should have taken them to climb the stairs for minutes, hoping he changes his mind. Nothing.
Eventually, I give up and state: "Ok, you pass under the great horned head above the entrance. After just a few steps into the darkness, the evil power overwhelms you, and you fall to the ground. Dead".
Still having the gut feeling of what was going to happen, but not quite putting a finger on it, I say that the other PCs see the corpses raise and vanish into the darkness - so as to leave me some room for damage containment later.
Dave and Fred said nothing special, but they clearly took it as a message that I didn't want Fred in the group (like hell! I say these things directly when I have to!); after five minutes or so and some not too enthusiastic comments, they declared that they had to go home. I felt sooooooooooooooo embarassed, but I just didn't know what to say. Before denying that I did it out of spite, the concept had to be made manifest, but noone at the table would mention it.
I've never seen Fred again, but I'm still good friends with Dave. He no longer plays much, but that's mostly because of busy schedule. I still regret not having seen clearly what was coming. I pride myself on my high empathy, but that day I must have really botched it.
As a player, I was fairly embarassed recently while playing Vampire - I was playing a Brujah (tough and fast vampires, among the best fighters) and, due to incredibly poor luck with the dice, I first accidentally started a fight when I just wanted to get this common street thug in a dark alley, and then got severely beaten by him on top of that. I ended up with less blood than what I started the encounter with, instead.
