I wrote a reply before I got this far down in this thread, but 100% agree.

So for that hour:

10min to stop the last thing I was doing.

10 min to switch to new task (getting environment set up, checking out code, etc).

30 min to figure out where I was the last time I started.

And now 10 min to actually do anything.

God forbid a random pop-in, priority email, slack message, system alert, etc happen in that hour.

Yep seems totally efficient to me.