Even grammar can be "moody," but grammatical moods express the attitude of what a person is writing or saying. The three grammatical moods commonly used in English are the indicative, imperative, and subjunctive moods.
The indicative (or realis) mood is used to make a statement of fact:
You cannot outlast us and we will defeat you.
Caption 19, Barack Obama's Inauguration Day - Obama's SpeechPlay Caption
You will learn the true nature of the society we live in.Play Caption
The imperative mood is for commands or requests:
Step away from your vehicle and put your hands on your head.
Captions 10-11, Movie Trailers - Men In BlackPlay Caption
All emergency service cars, please come to Vesey and West [Streets]!
Caption 4, World Trade Center - Story on the 2006 filmPlay Caption
The subjunctive mood is used to express a a wish, desire, or something that has not yet happened.
I'd like to have something interesting to do and I'd like to have nothing to do.
Caption 54, Leonard Nimoy - Talking about Mr. SpockPlay Caption
I would like to explain how we talk about the time in English.
Caption 3, Lydia explains - the clockPlay Caption