ha ha only serious: [from SF fandom, orig. as mutation of HHOK,

:ha ha only serious: [from SF fandom, orig. as mutation of HHOK,
`Ha Ha Only Kidding'] A phrase (often seen abbreviated as HHOS)
that aptly captures the flavor of much hacker discourse. Applied
especially to parodies, absurdities, and ironic jokes that are both
intended and perceived to contain a possibly disquieting amount of
truth, or truths that are constructed on in-joke and self-parody.
This lexicon contains many examples of ha-ha-only-serious in both
form and content. Indeed, the entirety of hacker culture is often
perceived as ha-ha-only-serious by hackers themselves; to take it
either too lightly or too seriously marks a person as an outsider,
a {wannabee}, or in {larval stage}. For further
enlightenment on this subject, consult any Zen master. See also
{{Humor, Hacker}}, and {AI koans}.
-- The AI Hackers Dictionary