I kinda get it. I get interrupted by so much random bullshit during the work week, focusing on projects is hard. Much easier to browse social media at work, respond to email, get out occasionally to do chores, etc. Some light productivity, but deeper concentration is hard.
Friday is usually my go-to project day. People tend to leave me alone enough so I can actually dig in. I'm content with my current situation so I don't feel a need to work on weekends, but I can totally see how that might be more enjoyable. Not working the entire weekend, just a few hours on Saturday morning where no one will fucking bother me. Could probably get so much more shit done in way less time.