Lacan’s jouissance is paradoxical enjoyment that reaches a painful, disruptive state: not necessarily ecstatic, but destructive pleasure.
Such a state can be neurotic: compulsively scratching your "itch" both soothes and traps the individual in a repetitive cycle (hoarding, grooming, sex, counting, organizing, procrastination, work-a-holic).
This "symptom" (Freud’s term) is an early compromise of conflicting desires manifesting in a distorted manner, a sign of unresolved unconscious issues. Yet, Lacan says we can recognize—and accept—our unconscious satisfaction gleaned from our symptoms: it is not merely a problem but a meaningful expression of the self.
Žižek
takes it further, saying ideologies are a collective "symptom" offering what feels like pleasure/enjoyment while masking deeper issues and contradictions. (For example, consumerism provides satisfaction and alienation; politics is often about tribal affiliation and winning over moral motivation.) Like Lacan, Žižek is not interested in eliminating the "symptom," which only moves the symptom elsewhere, but in learning from it.
To accept that our pathology is linked to—integral to—our identity reveals our uniqueness as "symptomatic" of our inability to handle conflicting desires: jouissance reveals our sickness, which is our identity.