Many have the mistaken idea that (trying to) do more than one thing at a time is an effective way to increase efficiency. But all it serves to do is distract our attention, and we cannot do any of the tasks with any great precision.
We end up doing things in a haphazard and sub-standard manner, or taking more overall time to complete the tasks.
Having a single focus at any one time is a great way to preserve that attention to detail that allows us to do exemplary work... and it's also a great exercise in mindfulness...
One of my favourite mindfulness reminders is to ask "What am I doing now?" and then to simply do that one thing, whatever it is, to completion, and with complete attention.
It's a great way to bring joy to mundane activities and attention to the things that really matter.