I feel this, however I live with my wife and child and am resolved to never being able to focus. I get up at 4:30 am to get 1.5 h for myself before I have to leave for work, but that usually gets swallowed up with showering, dishes and maybe yoga. Then I get the commute on the train and that's all the time I get to actually focus on anything. I put headphones on at work in order to be able to do it (and to mess around online like I am doing right now).

I've always assumed it's a neurological thing, whether ADHD, emotional abuse history, introversion; it could be interpreted as part of any of those things.