When I hit the brakes my eyes automatically go to the mirror to gauge how hard I can hit them. I don't know why or how I learned this but it happens involuntarily. For all I know everybody does that.
On what was probably my first turn behind the wheel with my dad, he told me to always keep an eye on the rearview mirror. Being a dumb kid I took him literally and tried to actually split my vision to always be looking both ahead and behind. Gave me a headache. Also on that first trip I came so close to a parked car while passing an oncoming car that my normally mellow, undemonstrative dad let out a startling yell.
While we're at it, I haven't had a ticket or traffic infraction (knock on wood) in at least 15 years. There should be top-notch super cheap liability insurance for people like me. Take it away for any moving violation, fine, but now I'm just a cash cow for those bloodsuckers.