Annoying is when you sit down and write something perfect, and then you mistakenly end up erasing it and can't get it back. Then you realize that it took all the energy you had to write that, and you're now starting to get a headache and you also see that the battery on your laptop is running down and you don't have the energy to plug it in.
And your head is really starting to hurt. So, instead of trying to find the words again, you shut down your computer and take a nap. A much much needed nap.