I don't understand...

[Foo01]

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The last boss took 3 doors. This was the run I actually had to leave and come back as a tank because the original was gone. Luckily, we got a replacement DPS that actually pulls their weight so we didn't run out of doors.
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It alll smells like a troll you got. The tank got sick of the troll and left. Why did you feel that you need to come back be subjected to the troll? If I was the tank I would have ask the party if they think this guy was a troll especially if we were wiping multiple times because of the troll.

BTW what sort communication did you have with the BLM? Without further information you cannot determine how to make the call on this. But please don't generalize 1 player's bad behavior or the select few bad encounters that stick out and to say the rest of the player base that they don't care about their performance.

Here's the problem. As your average player runs into more and more militantly casual players who refuse to accept advice or tactics....

Come again militant casuals? Seriously? Does this even make any sense? Casuals don't care enough to be militant, beligerent, or any these troll behaviors. Those are trolls. Don't blame casuals for grief trolls cause. Who knows how trolls operate, but it doesn't take a genius to guess that trolls will hide under the guise of noobs/smurfs and try to grief your game. Vote kick them and report them.

I prefer not to talk about trolls because they are very rare (for comparison much rarer than the elitist speed runner that rage quits). In any case, this was a while back, but I had troll tank in Haukke manor normal on low level roulette. I was a healer, the tank ran off before even protect and got himself killed. I asked if he was new so we can have a game plan. So he started yelling about no heals and how he had a iLevel89 Bard, and then sat down at the bottom of the stairs demanding an apology. We vote kicked him and he joined back twice in progress and continued to demand apologies, eventually we just left. These militant types are never casual. The casuals don't have enough time to play as it is to waste their energies being militant. Needless to say, this one of the handful of trolls I ever had to report. I provided the GM all the chat transcripts and talked to them to help with their investigation.

.... turn more and more to statics and refuse to pug. The casuals run out of people to pug with as they can't clear content and quit. New players come in and can't find groups because everyone is already in a static.
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Let them play as they want kills games just as effectively as you suck newb
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This such bunch of BS. The elitist form their secret society of statics and exclude other players and keep people out, because that is what elitist want. And then they don't want be rubbing shoulders with the unwashed masses and leave the noobs to flounder on their own. Letting people play as they want was never the problem. Forcing people to play a certain way is what will drive the new players away. Trolls don't help, but to blame it on casual players this way is completely and utterly false. I wouldn't be surprised on bit if some bored elitist decided to troll thing like low level roulettes just to drive the new players away, because they only feel special if they up everyone else down.