In my opinion, we can accuse Guevara of many things, but selfishness is not one of them.
First, giving up a pretty high social position (doctor, from a well-to-do family) to help what was quite frankly an unlikely revolution in Cuba. Then, leaving Cuba, and a guaranteed position in the government (cushy job), to start from scratch an insurrection in Bolivia for several years. He gained absolutely nothing for himself, but gave up his life.
@BNS
I'm curious, how did the revolution destroy Cuban unity and spirit?