You gotta pay to live in paradise. I can be on the beach in 15 minutes. From an Oklahoman's perspective, I am basically on vacation year-round.
Traffic is awful
Metro rail is not complete coverage, however the extension out to Santa Monica (West LA) is opening early 2016. As you say, the buses get mired in traffic all too often.
sounds obvious right? yet people still try to do it for some reason. just pick a part of LA and spend a day or two there. it's not hard
Yeah. If you go to Paris or Tokyo or Mexico City or Seoul you can go to multiple parts of the city. Don't try that in LA.
Cities with first world infrastructure make it reasonably easy to get around like that, LA doesn't.
But that shouldn't ruin your trip. There's plenty to do around Hollywood or Santa Monica or wherever to keep you happy and learning new things for a few days.