Doing several things at once is a trick we play on ourselves, thinking we're getting more done. In reality, our productivity goes down by as much as 40%. We don't actually multitask. We switch-task, rapidly shifting from one thing to another, interrupting ourselves unproductively, and losing time in the process.No one is exempt from this, but some people are better at switch-tasking than others. For my part, I try to put my all into whatever I am doing, ergo I am a big proponent of single-tasking.