Northern California is beautiful... I will give it that... but it s kind of boring and cold... and yes I will admit L.A. can seem a bit dirty because it is a HUGE county... so it has some nice parts and its ghetto parts but L.A. is tons of fun with lots to do! Just visit and see if you like it... San Diego is nice too but a little more dull than L.A.
Northern CA is the best. Like Tahoe and Truckee its really beautiful, and not dirty. It is cold though! but if you go in the winter, you can ski and board, which is absolutely amazing ! when people think of CA, they usually think of LA, but there is much more to it! Nor Cal is definitely the way to go!