People enjoy their work in different ways. Some like being 100% on their main project, some like involving themselves in many smaller efforts (both across their

People enjoy their work in different ways. Some like being 100% on their main project, some like involving themselves in many smaller efforts (both across their main project and across 20%). Also, the default state is to not have a 20% project, the only people that will work 20% on something else are those that made a specific effort to do so.