I drive the 5 and 405 in California frequently and I always leave two lengths because people are crazy and I like my car.
Of course if I see where I can cut through and get around a clump of traffic I will break my rule, but in general it makes no sense to endanger yourself just to close gaps and get to your destination seconds early; I'd say you have emotional issues if you're the type who does this often.
You must live in SoCal too. The 5 and 405 are two of the biggest pieces of shit in LA. I used to drive the 101 every day. My god it sucked.
But yeah, leaving two lengths is the right idea. Better to be safe and lose a bit of time than rear end someone. I have personally witnessed two collisions, and one of them was a really bad rear end collision (3 cars because some stupid woman was looking at her phone).
For TC, it's pointless to be upset by driving defensively. Just protect yourself and don't worry about it. Also, pay attention to those truck drivers as they get crazier by the day, at least here in southern California. I even got clipped by one who was tailing me for no reason. Even had to call the police as the guy was screaming in my face. At least his company covered the repairs, but yeah, it was an unpleasant experience nonetheless.
I hate the 101 even more than my normal drive. At least the 405 has predictable rushes, the 101 seems to be ass at all times of day save for the witching hour.
Every once in a while you see a couple people in a crash in the fast lane trying to dodge traffic while yelling at each other. Not only do these people seem to not realize that they did something stupid and caused their accident but they increased everyone's commute by close to an hour. I intensely dislike these people and seeing people brag about driving stupidly triggers me. ---
...Dude, you're a ****ing douche. Get off my god damn internets. - RX7Infinitilll