Still, millions of people manage to make it work somehow, so I guess you eventually get used to it and plan accordingly.
Holidays are usually the worst of the worst. For a few years I drove from the east part of LA to Vegas for Thanksgiving (not having to drive through LA). That 4 hour drive (admittedly a bit longer on a Friday) took 13 hours; 1pm - 2am.
What's unfortunate is in LA it is not just that there's rush hour on the weekends, it's all over and at odd times. 9-5 workers have accommodated the situation so long that leisure time is regularly constrained.
Yeah...people here in the Bay Area say traffic is bad, but it's mostly concentrated at rush hour. In LA, I recall traffic jams at 11:00 PM. You don't see that much in other places.