In grammatical terms, the mood and tense of a verb are often discussed together. Tense is a much more familiar concept for non-languagefreaks. "I am eating" and "I have eaten" are two different tenses of the same verb that each indicate when the action happened. Mood is not as simple. It refers to different levels of possibility and potential. You can talk about things that might never actually happen by changing the mood of the verb. "I don't eat horse," but "I might eat horse if someone said I was too chicken shit to try it." Those two sentences are the same verb in two different moods. If you have studied a romance language, you might remember the difficulty of trying to remember how and when verbs take the subjunctive mood, something that doesn't really exist much anymore in English.
In much the same way that our understanding of past, present, and future often goes awry, we can easily confuse things that are true with things that could be the case. Here is a fictional example.
A brother and sister live together and share a car. Rosita goes for a walk one Tuesday afternoon and comes home to find that Enrique has gone somewhere and not left any note about when he will be back. Rosita is on a Jujitsu team that practices every Tuesday night. When she sees the car isn't there, she gets furious and goes through the following thought sequence.
- Enrique took the car.
- He must not want me to go to Jujitsu practice.
- He wouldn't do that if he really cared about me.
Here's what really happened.
- Enrique got a call from a friend who needed to be bailed out of jail.
- He got really upset because he was worried about his friend.
- He took the car forgetting momentarily in his emotional state about Rosita's Jujitsu.