So apparently human are not equipped to multitask unless you consider listening to music while doing your work, multitasking.

In some science study, people that multitask show a degradation in many of the abilities thought to be enhanced from doing multitask type work. Things such as, being able to jump from one task to another or to quickly disseminate information is actually crappier if you tend to multitask a lot. This explains why some of my co-workers are so fucking scatter brained.

If you're going to do something, focus on doing just that one task and do it right. Plan out your tasks for the day and become a a fucking zen master at it. Then execute each of those tasks like a fucking ninja. Otherwise, you're just wasting everyone's time and making yourself be closer to that bag of shit you really are.

Source: http://lifehacker.com/5922453/what-multitasking-does-to-our-brains