I have this problem in a big way, too. I haven't permanently cracked it, but I can crack it here and there. Basically when I get free time and notice I'm defaul

I have this problem in a big way, too. I haven't permanently cracked it, but I can crack it here and there. Basically when I get free time and notice I'm defaulting to "I'm gonna go <slack off> now", I immediately replace that with, "Actually I'm just gonna do this one thing on that project". Inevitably, I get sucked into the project until something breaks my flow. The more consistently you can do this, the easier it gets because then you develop a sort of "passive flow" where a perpetual background mental process gets pulled farther forward to where you can't wait to get back to working on the thing, whatever else you're actually doing. And between failure and success, I'm far more scared of success. Failure is demoralizing but at least it means you can put a pin in the thing. Success means people probably now have expectations of you.