Yes, Kierkegaard certainly considers regret useless in that sense, but it is very easy to go from a position of not regretting things into a 'the dude' style in

Yes, Kierkegaard certainly considers regret useless in that sense, but it is very easy to go from a position of not regretting things into a 'the dude' style indifference. He makes very clear that there is a difference between spiritual despair, which can exist even when mind and body are seemingly at rest, and that one need not even be aware of that despair. It's one thing to consciously reject things that have no deeper meaning, and to engage with one's own mind, but in particular nowadays an attitude of indifference is also common. That is to say rejection of superficial things not because you're truly discovering your mind/spirit/faith etc but simply for safety and contentedness. And I don't think Kierkegaard had the intention to advocate for this kind of withdrawal.