One of Kundera's themes is arguably the question of whether Communism can in fact be reconciled with tradition and a reasonably "normal" type of existence. The protagonist, Ludvik, is plunged into a kind of madhouse when a joke on a postcard lands him in a labour camp as an enemy of the state.

Kundera's answer to why anyone would prefer a totalitarian system is revealed in the motivations of the character Zemanek, a party ideologue. Zemanek revels in power, but it's basically the power of a small-fry in the overall system. He's a symbol of that tendency in human nature to feel more important than one really is, to lord it over other people, particularly by exploiting their weaknesses.

Others cling to the regime chiefly out of fear. Once unscrupulous men have come to power and established a dictatorship, the tendency of many is to fall into line with it, preferring the pedestrian role of conformity to individualism. This is what Ludvik's girlfriend, Marketa, does when she turns over the offending postcard to the authorities. This was the "safe" thing to do.

Fear has a domino effect in a society such as this. One person after another conforms to the requisite behavior because it has become the normal thing to do, superseding conscience and any traditional sense of fair play.