ATTPQOTD: I live in northern New England, so there are hills everywhere.
ATTQOTD: I do stop sometimes. Like others, I am an interval runner, so there are always walking breaks, but right now I've also been coordinating my long runs with my running group's long runs, and my long runs are longer than theirs, so I start before the group starts, then meet up with everyone before we head out. I've gotten pretty good at timing my pre-miles to end right at the time we're supposed to be meeting up to head out, so I'm usually only stopped for 5 minutes or so and I use that time to eat my first gel if the run is long enough and get my water bottle and stuff.
I also do stop at the water stop that we put out to eat gel and refill my water bottle, and maybe retie my shoes (my shoes always get looser when my run goes on, like the laces seem just as secure as they were when I left but I think my feet deflate a bit

), but I try and not dawdle doing that. Never bathroom stops, though... I've never stopped to use the bathroom before during a run or a race, except at Tink when I had to spend so much time in the corrals before we started... I should have left the corral and peed again before the race started but I didn't want to lose my spot near the front of the back corral. Before group running, I did used to pause to run into a convenience store or Dunkin Donuts 1-2 times per run to buy a water refill for my handheld bottle. We don't have outdoor fountains, so I used to have to plan routes that would go past places selling drinks at the appropriate mileage points.