Today I've discovered new way to concentrate during writing. Earlier I wrote almost all texts using OpenOffice or Google Docks at home and Microsoft Office at the work. Each of these software has a lot of tools, that are not always really required. So sometimes Instead of working I stopped and used different options, for example changed fount, made it bold, etc. Big number of tools distract from work. For example checking spelling knocks thoughts strongly. In addition sometimes text editor automatically replaces words when it is not needed, and this is annoyied too.
But now I get to know that there is another type of text editors - room-editors, that are easy and do not contain any tools. In fact these editors do not have buttons at all. So nothing distracts you during writing. Working in them you can see black screen and your text only.
DarkRoom is editor of such type for windows. I've download and installed it to comp at my work
PyRoom is editor of such type for Linux. I installed it at my laptop.
http://writer.bighugelabs.com/ there you can find online room-editor.
Definitely there are a lot of such editors for MAC.