I obviously know more about your class than you do, play how I tell you.

[Nukocafe]

I REALLY hate running into these types of players, typically raiders(not all raiders of course).

As someone on the other side, I will never hesitate to tell a white mage to STOP using fluid aura.
Just because someone tells you how to play your class - doesn't mean they don't know how to play it. By now a lot of people have leveled up most of their classes and have experience playing most of them enough to try to give advice. If they're being rude and deconstructive, that's another story...but if someone is seeing someone completely doing bad as their class, I think offering CONSTRUCTIVE criticism is always a plus.