These are some examples of the useless lame-o PCs I have seen --
*Most often the PC hides in combat and just sits there. Not launching sneak attacks from hiding, just sitting there like a bump on a log. I have played with rogues who spent combat looting the bodies while the rest of the party was still fighting the enemy.
*One of the worst examples was a ranger who began
playing cards during combat. When confronted he said he figured we had it under control. A strange conclusion since several PCs were down to less than 1/3 of their hit points. That was when my fantasies about a higher power smiting the player from the game began.
*There was the wizard whose primary tactic was to cast
invisibility on herself and then sit there doing nothing for the rest of the combat. When confronted about this she said she did not want to break her invisibility. She refused to change what she was doing. I wonder if she would have changed if the campaign advanced to the point where she had
improved invisibility but she was kicked out before we got to that point.
*The "fighter" with strength 11 and charisma 17. He insisted on fighting with a longsword and was completely useless in combat. The DM gave him a rapier because he had high dexterity. He said the rapier was not his style and threw it away! He continued to be a total waste of space and was always going down.
*The human cleric whose primary tactic was to cast darkness on himself and run around in circles so enemies would not hit him. He could not see in the dark. Round after round he would run around in his darkness. I suggested to the group we kick this player out as he was the one who in an earlier campaign ran the ranger who started playing cards in combat. They would not do it.