Why Only Do One Thing?

Why only do one thing when you could do a multiple things at the same time? I'm not referring to projects or anything, I'm just referring to how it should be possible to do multiple menial tasks at the same time, and not be crippled to only do one. Like say flipping between a movie and the html for the website. Why can't I decide that I've done enough of the complaints and continue with something else?

To add onto that, if I forced myself to work on the website it would ruin it for me. Nothings good if you don't take breaks, they're necessary to make things bearable. I do this website by thinking about a concept, and then ranting about it. I don't sit at a desk and bash my head until ideas come out. And I don't force myself to post every week. What good does posting at a frequent time do if it makes me run out of ideas. Because of this, I have to take breaks.

So why should you, the reader, do this too? Sometimes you do have to focus, maybe on a project, or maybe on a book, but why do something exclusively? Why treat a gift as a liability? And finally, if you have to force yourself to do something, should you even be doing it?

Sincerely

Someone annoyed by too much focus