I am a Bellevue native, but have lived in the bay area for 15 years now. Californians are "ruining" Seattle in a way it would be inappropriate to say about foreigners. Fortunately the only thing "ruining" the bay area is "techies", not people from a specific geographical location.
Oh, and the traffic has always been beyond abysmal, Seattle. You know it, and I know it.
I like to joke that nobody ever thanks me for moving to CA, the way they viciously gnash their teeth about all of the horrible Californians moving north (been whining that way at LEAST as long as I can remember, into the 80s, but I've heard it predates that by many decades).
Funny, I know more people who have moved from the PNW to CA and particularly the Bay Area than the opposite. Offhand I can only think of one person who moved north who wasn't returning 'home' after college.
I like LA b/c no one gives a crap since everyone is from somewhere else and the city just absorbs you.
My home state of N Carolina has a lot of people move down for more affordable housing and decent jobs from up north. The city of Cary (near Raleigh) is casually joked about as the Central Area for Relocated Yankees.
No one really cares outside of joking about their poor tastes in sports teams.
Oh, and the traffic has always been beyond abysmal, Seattle. You know it, and I know it.