Bad players are:
Adrenaline junkies who don't care about story, lore, or worldling, and only play RPGs because they don't quite have the reflexes for FPSs.
People who buy story skips and level boosts for their first character.
People who only do what they need to gear up for and complete the latest raid and say there is no more content when they have only done 1% of it.

Those are all filthy, stinking casuals in my book.