A mood in grammar is a verb form that depends on how its containing clause relates to the speaker’s or writer’s wish, intent, or assertion about reality. Mood is distinctive from tense (how a verb's intent relates to its location in time) and aspect (how a verb's intent relates to the flow of time).
There are considered to be three different categories of 'mood': realis (how a verb's intent is to display a fact or declaration about reality), irrealis (how a verb's intent is to indicate an action not known to have happened for a fact), and interrogative mood (considered by some to be an irrealis mood, this is a mood used to indicate a question).
So which language has been found to contain the most irrealis moods? How about, which language contains the least amount of irrealis moods? Or, which language most commonly uses irrealis moods in day to day conversation?