Right now, most of my day is killing time on the internet and playing computer games. And I'm OK with that (right now.)
I've had really productive periods in my life. I really enjoy them, but they generally do not happen accidentally. What seems to work for me is to identify all the things I'm doing wrong, and replace them with doing the right things. (Surprising, right?)
Part of what helps is the cumulative effect of replacing bad habits with good habits. Things like having a few drinks at night, staying up late, not exercising enough, and eating foods your body doesn't handle well all add up to a state of mental fogginess, lethargy, distraction-seeking, as well as the cycle of going back to those same bad habits to get over it.
I've done things like the Whole30 diet, where I avoid any likely trigger foods for 30 days so I can experience a healthy digestion system, and (ideally) phase bad foods back into my diet so I can identify the worst offenders. I'll set a "this is my personal universal law" work out schedules that I prioritize above anything else. I've gone without drinking for months at a time. I'll cut out things like Facebook, Instagram, addicting computer games, binging of TV shows, etc. and replace them with educational books, programming tutorials, writing down ideas, making projects (woodworking, code, etc.)
The cumulative effects cannot be overstated. I'll spend my days with a clear head, with the energy to keep doing the things that benefit me, the interest in the projects that I value and consider productive, often a repulsion to sugary foods, a much lower appetite for frequent snacking/grazing, a somewhat natural urge to go to bed when I'm tired and repeat the process the next day.
So those periods are excellent, and I miss them when they are past. But I also eventually miss my bad habits as well, and inevitably let them trickle back in, reversing the cycle in the opposite direction. I have not found a perfect long-term solution, but I know that when I miss productivity enough or feel depressed enough about being so inactive, I'll probably be motivated enough to sit up and take action and get back into the upward cycle.
I suspect the most successful people tend to avoid the trickle of bad habits, or just have a better handle on keeping it at a trickle while they stay in a more optimal state. (And otherwise have factors like luck and good connections on their side!) But I'm content (most of the time) with a life that is sometimes really productive, and sometimes much less so. And I come to accept letting go of those golden ages and embracing the less productive consumption ages as something I can enjoy without overshadowing them with guilt. Your values may vary!