Blanca raises a good point: you do something often enough, you get more comfortable/competent doing it.
Another lane splitter here, being doing it for over 20 years now. Recognize and respect the risk of doing so everytime I do it. Almost to the point of being paranoid, I always ride with the mindset that cars are not watching and will not see me, always scanning 360-degrees and anticipating/planning for worse case scenario.
Definitely not for everyone, I see lots of SoCal riders who do not split lanes. People who do it, get it. People who don't, don't.