What you are talking about can both be true, that our individual actions matter as part of a whole, but by themselves have very little power. Its sort of like a big ocean of water, very powerful when moving together. Take a bucket of that water and it loses a lot of its overall power but the individuals drops are the same as they've always been, and they work together with other drops just the same.

The drops aren't aware of the bucket size or much past its immediate neighbors, but together with the other drops they can do more than a single drop could.

If we lose some drops, thats not a big deal, they didnt contribute much individually, but if we lose more drops than we take in, that is a big deal.

In this way everyone's actions are both important and insignificant.