Parts of it are sleepy, parts of it arent. But really its just endless tract housing and strip malls.

(also similar: minimal amount of nature within the city itself; lots of concrete but not in an elegant urban way; not much in the way of historical sections)

Parts of the western San Fernando valley, which lies within LA proper, are not that dissimilar from SJ.

And, when people say "LA", they really mean the LA area, which contains not only the city itself, but outlying/surrounded cities like Pasadena, Santa Monica, Compton, Long Beach, etc.