A dark and terrible side of this sense of community of interests is the fear of a horrible common destiny which in these days of atomic weapons darkens men's minds all around the globe.
I think the importance of doing activist work is precisely because it allows you to give back and to consider yourself not as a single individual who may have achieved whatever but to be a part of an ongoing historical movement.
When you read a classic, you do not see more in the book than you did before; you see more in you than there was before.