My main interests in OSM, are mainly in relation to outdoor living - mainly hiking and cycling. OSM could be a huge asset in this area, sins the locations paths camp sites etc. are constantly changing, and keeping up with these are usually of a low priority with the various mapmakers and governmental bodies. Especially in the less populated areas. However there often is a huge community that has a close and intimate relationship with these areas.
Also I enjoy discovering my local neighbourhood wherever it happens to be at the moment. Mapping my neighbourhood seems to me to be a great way to connect with my surroundings in a more intimate way. I think if more people did that, it would develop local communities around the world, and create a stronger feeling of responsibility for the area outside ones particular home.