Seth Godin often talks about the idea of serving one customer at a time. The one customer that is in front of us right now, because they don't care about the hundred customers that came before them or the ones that will come after. Whether they like your product or your service is solely determined by the experience that they have in interacting with your product.

This is a concept that has wider implications than serving customers, of course. 

It is the core philosophy of mindfulness. The act of being completely present in the moment that is now, without distraction and without being caught up in thoughts about the past or the future, or to something that we are not directly experiencing right now. 

We often choose to multi-task because we feel that's a more efficient use of our time. 

Multi-tasking only works when it uses different senses that don't compete with each other. For instance, listening to a podcast while cooking dinner. However, listening to a podcast while writing a blog post, as it turns out, is a less efficient use of our time than doing them one at a time serially. 

This is due to the overhead that switching context adds to the tasks that we do. 

One thing at a time.