Yep, it might be because they are repetitive activities. We tend to have tunnel vision going.
You know ... the whole laser focus on the one thing, the substance of choice. It translates well into a repetitive activity.
We were stuck on drinking/using, and in getting sober, until the brain totally heals, there's that tendency to find ruts in everyday life.
I did, anyway. I would find myself getting stuck on something and would have to pry myself away from it and move onto the next thing.
Also, read up on neuroplasticity, as it might explain lots of this as well.