What tone or attitude toward the character and the audience do the idioms create?

Idioms add color to the characters in the story. The combination of figurative and literal meanings sparks the imagination of the audience. They also add a sense of humor which makes the story more appealing to the audience. Idioms create interactive effects towards the listeners and/or readers.

It is false my dude.

Well if some words are like big you could say enormous .just make them sound more egxarreted