I was working at a fairly small company who tried to do the whole 20% thing. For me it was awesome as I got to work on some really valuable things without all o

I was working at a fairly small company who tried to do the whole 20% thing. For me it was awesome as I got to work on some really valuable things without all of the bureaucracy around project management. For the more junior folk though it seemed like a waste of time as their stuff seemed more fun than valuable to the company. At Google/Atlassian is it entirely 20% on what you want or do you first need to propose and justify the value of the work you plan to do with an approval?