You are officially in la-la land, at least according to the latest update in the Oxford English Dictionary, the bible of our language
We were never partial to the term. City of Angels, yes. L.A. Of course. But la-la land always seemed to sound like something outsiders would use to describe our fair city.
Nonetheless, the Brits at the OED set it in stone:
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la-la land n. can refer either to Los Angeles (in which case its etymology is influenced by the common initialism for that city), or to a state of being out of touch with reality--and sometimes to both simultaneously.
We particularly love the idea that being out of touch with reality will be forever linked to this town.
There is some truth behind it. Look at Charlie Sheen.
[Spotted at LAist].