The rule of work to be done versus time available

Having finally settled down from the office move and worked through the overflowing pile of stuff in my in-tray I thought I could spend the day leisurely working through all the little things that aren’t quite so urgent but need to be done at some point. It doesn’t seem to matter how small the pile of work in my in-tray is though, somehow it seems to magically multiply to take longer than the time I’d planned to spend at the office. Even when I plan to work late. Looks like the little things will have to wait a bit longer...