la-la land:
1. Los Angeles, California (often abbreviated L.A.). This expression pokes fun at the alleged eccentricities of the city's inhabitants. For example, What do you expect? Frederick has lived in la-la land for ten years and it has rubbed off on him . [Slang; c. 1980]
2. A state of being out of touch with reality, as in "I don't know what's going on with Amy - she seems to be in la-la land'. [Slang; c. 1980]