Many of the characters seem to have something in common so far - they see people as they want to see them, not as they really are. Please feel free to add to the list!

Edmund - He thinks Mary is just as sweet as Fanny, and that she gives opinions that are not her own.

Henry - He thinks that Fanny has some regard for him because she is polite.

Mary - She thinks that Fanny will think like she does about how she soothed Mr. Rushworth during the rehearsals (this of course is just one example).

Sir T - Just about everybody - he thinks they will think like he does because he wants them to.

Lady B - well, she is a puzzle, I'm not quite sure what she thinks. I suppose she thinks whatever Sir T thinks, so she doesn't count in this.