lies fallow, it is necessary to see this phenomenon as a fundamental existentiale, and to outline its structure.
Both the undisturbed equanimity and the inhibited ill-humour of our everyday concern, the way we slip over from one to the other, or slip off into bad moods, are by no means nothing ontologically,1 even if these phenomena are left unheeded as supposedly the most indifferent and fleeting in Dasein. The fact that moods can deteriorate [verdorben werden] and change over means simply that in every case Dasein always has some mood [gestimmt ist]. The pallid, evenly balanced lack of mood [Ungestimmtheit], which is often persistent and which is not to be mistaken for a bad mood, is far from nothing at all. Rather, it is in this that Dasein becomes satiated with itself. Being has become manifest as a burden. Why that should be, one does not know. And Dasein cannot know anything of the sort because the possibilities of disclosure which belong to cognition reach far too short a way compared with the primordial disclosure belonging to moods, in which Dasein is brought before its Being as "there". Furthermore, a mood of elation can alleviate the manifest burden of Being; that such a mood is possible also discloses the burdensome character of Dasein, even while it alleviates the burden. A mood makes manifest 'how one is, and how one is faring' ["wie einem ist und wird"]. In this 'how one is', having a mood brings Being to its "there".
In having a mood, Dasein is always disclosed moodwise as that entity to which it has been delivered over in its Being; and in this way it has been delivered over to the Being which, in existing, it has to be. "To be disclosed" does not mean "to be known as this sort of thing". And even in the most indifferent and inoffensive everydayness the Being of Dasein can burst forth as a naked 'that it is and has to be' [als nacktes "Dass· es est ist und zu sein hat"]. The pure 'that it is' shows itself, but the "whence" and the "whither" remain in darkness. The fact that it is just as everyday a matter for Dasein not to 'give in' ["nachgibt"] to such moods—in  other words, not to follow up [nachgeht] their disclosure and allow itself to be brought before that which is disclosed-is no evidence against the phenomenal facts of the case, in which the Being of the "there" is disclosed moodwise in its "that-it-is";2 it is rather evidence for it. In an
1 In this sentence 'equanimity' represents 'Gleichmut', 'ill-humour' represents 'Missmut', and 'bad moods' represents 'Verstimmungen'.
2 '... den phänomenalen Tatbestand der stimmungsmässigen Erschlossenheit des Seins des Da in seinem Dass ...' It would be more literal to write simply 'in its "that"'; but to avoid a very natural confusion between the conjunction 'that' and pronoun 'that', we shall translate 'das Dass' as 'the "that-it-is"', even though we use the same expression unhyphenated for 'das "Dass es ist"' in this paragraph and in that which follows. (The striking contrast between the 'Da' and the 'Dass' is of course lost in translation.)