> Everything below L4 is _incredibly stressful_ and unpleasant to drive, because you have to be constantly aware and alert without having anything to do.

Hasn't been my experience for the past year or so, give it a try sometime. Incredibly relaxing and frees up my mind to focus on potential hazards further than just one car length in front of me. Sometimes (don't hate me) frees up my hands/eyes to handle other things that need some temporary attention. Traffic jams, getting cut off by impatient drivers, being stuck behind slow drivers, none of it bothers me. I'm chilling out and talking to my kids and enjoying the scenery.