It's a well-known "rule of the internet" that there's a relevant XKCD comic for pretty much every occasion. This particular strip, though, is one I've never seen mentioned, but I've been reminded of it more times than I can count. It has kept me going during times when I've felt overwhelmed and inadequate in the political activism that I've done, and it has kept me grounded when grappling with others' commitment towards tactics that strike me as woefully ineffective.
It's my belief, and it's become kind of a personal mantra of mine, that apathy is our only impediment to revolution. We on the left are lucky enough to not only have the facts and arguments on our side, but the numbers as well; most people, if you sit down with them, recognize the unequal and unjust nature of our world, because that inequality and injustice serves a small, powerful minority at their expense.
Now some people, of course, are apathetic about this at face value; life isn't fair, they say, and equality and justice are only good in theory. But others are genuinely sympathetic to leftist complaints, and only complicit in our current system because they think it's unlikely to change, and life conditions all of us to avoid investing our mental energy into "pipe dreams". Either way, apathy is what stops both of these groups of people from being valuable assets in any socialist movement. If this collective apathy magically went away, there would be - at the very least - an unprecedented wave of global strikes, blockades, economic sabotage, etc. that would signal the beginning of a permanent seismic shift in politics forever.
It's unfortunate for us that the more perspective we have on the immensity of the world's problems, the more overwhelmed and mentally paralyzed we are prone to be. The challenge for us is to fight this tendency of ours with everything we've got, and to help others in their struggle to do the same. As best I can, I try to keep myself from spiraling into despair and hopelessness, and I try just as hard not to let my words send others down that path. Charity obviously isn't enough, and it can often reinforce apathy by acting as a means to easily dispose of one's guilt for a small fee. But it's better than nothing, and if someone has genuine concern for others and the desire to make the world a better place, all I can do is try to be a positive influence on them, rather than a thorn in their side.