"I play the way I want" -Randomperson

[Ghishlain]

So unless you play the class/job you wouldn't know.

Maybe it's just me, but I like broadening my knowledge and there are some basics each DPS class needs to do to maintain "decent" DPS on a target (and you can check my lodestone, I don't have a physical DPS properly leveled yet)

DRG - Maintain Heavy Thrust
MNK - Maintain Greased Lightning III
BRD - Maintain Straight Shot and maintaining procs on the target
BLM - Maintaining Astral Fire III up time for as long as possible; making the proper changes to Umbral Ice for MP regeneration
SMN - Maintaining DoTs on the target for as long as possible; using Aetherflow charges for Fester (though Fester usage is indeed harder to notice without knowing the class more in depth)

Again, as I've said, I personally like broadening my knowledge of the game mechanics and dynamics, so some of these facts that may come second nature to myself may not be for anyone else, but I'd like to think this is a decent baseline for the majority of players.

Also I've played with many horrible BLM's I don't go ballistic because they don't play like gods.

No one but the most hardcore elite of elite expect people to play like Gods. They are expecting them to know their role + class/job well enough to help defeat mobs in a timely manner based on their gear score.