"valley of salt tears" and "dark, deep and foggy" are to images used to establish a mood of?

The mood is dark.

Examples of happy mood: Bright colors, birds singing
Examples of dark mood: Black and white (or monotone), quiet

Note: If a scene is described as "quiet", this doesn't necessarily mean it's dark, but it could be peaceful, so you want to look at the other describing words. For example; Quiet, soft colors, heavenly, etc. is considered a peaceful mood.

do you mind if i don't come to the gym with you.