Don’t even have ADHD (I don’t think), but this happens all the time with house projects. A seemingly trivial task that I think will only take less than an hour suddenly takes up my entire day as one small part of the thing suddenly goes awry and I get half a dozen smaller tasks just to account for fixing that small thing that tripped up the original task. By the time I finally get back to the original “trivial” task, my day is already fucked.
“Oh shit, stripped a screw and this is about to fall apart, I’ll need to go to the store to get a new part for this. Should be pretty standard, I’ll probably find the part right away.” Get to the store. “Oh shit, there’s like 5 different standards for this thing and none of these exactly match the original thing I had, but I didn’t bring the part, so I can’t even compare. This looks closest to it though, I’ll just grab this, it should work.” Get back home. “Goddamnit, it’s not the right part, it’s off by like 1/2 an inch, shit, I need to take this back and get a different one.” Back to the store. “Ok, this seems to be the right thing, but there’s some extra mounting that’s needed, but what I already have at home should work.” Get back home. “GODDAMNIT.”