Millions of people world wide love to write.  Others hate it with a passion.   Regardless of which end of the scale you fall on, following the Writing Process will make whatever writing you have to do more effective and easy.

The mistake usually comes when you're in a hurry to write something.  You think you'll get it done fastest by just writing the thing and being done with it.  Unless you don't care at all about the quality (and sometimes even then), you could actually save time by slowing down and taking a minute to run through the steps of the Writing Process.  

Try it.  Once.  A few times, even.  You'll find that even following the Writing Process a few times will raise your awareness of the steps and they will happen more naturally even when you don't go through them on purpose.

Don't skip the pages about other important concepts like Purpose and Audience, either.   Those two are the two most important concepts you need to understand thoroughly to become an effective writer.  If you don't have a clear idea of what your purpose and who your audience is, you'll experience a lot more confusion and frustration as you try to write.