No accounting for morons. I live in the 'burbs, and I go a couple of miles out of my way on my commute to use less traveled (but still 4-lane) roads. As a result no driver is more than minimally inconvenienced by my presence, so if they have a problem with it they can kiss my butt. I rarely have a problem. Then again, my community is pretty cyclist-friendly. I used to live near LA, so I can imagine how your experience as a commuter might differ a tad from mine.
All I can say is stay safe. The mirror is a good suggestion. Other than that, best thing to do is just be predictable to drivers. If you're switching between taking the lane and riding in the gutter a lot, it may be worth it just to stay in the lane for a while. If people have a problem with that, tough. I try to accomodate drivers when possible, but not at the expense of my safety.