It is helpful that the main screen shows which Superchargers are full and which have empty slots.
Sometimes easy to just skip the busy ones and grab the next one within range, on your trip.
Seems the most congested areas also have the most congested Superchargers. Few congested Superchargers on the open road, except between two congested cities.
Tesla is being agressive in constantly rolling out additonal charging options in congested zones.
Almost 50% of all Tesla's sold in the USA are going to California. There is just a massive amount of Tesla's here and they all want to charge. The fact that most get charging for free makes it worse.
I gather it's to attract more to the area? I go to the stonewood mall one on firestone. it's never full. It's also great having the next closest one nearby as backup. The 30 minutes you wasted waiting at the other ones, you could have topped off at the Downey ones (as long as it was along your route).
All your other locations are super high traffic. I never bother with the BP one anymore, feel like that one is abused the most.