Most of the time, like 3 from 5 runs. We just don't notice it because the other dps/healer is picking up their slack. Or you don't notice the lack of heals or tank cooldowns because youre a dps. If we would have a parser(because without it you can't see said person spamming only 1 button /sarcasm), we could probably kick half the people in 8-24 man stuff, but that would be toxic.