I'll give Dungeon/Trial or Raid advice if I see problems reoccurring. If I see someone make mistakes playing their Job I'll give advice. But the moment I get a response that says "Don't tell me how to play my job" I just let them make mistakes at that point.

More often than not you get the "Don't tell me how to play" response or you get absolutely nothing in return. Very rarely do you get a "Oh cool I didn't know that thanks!" reply.