The Unbearable Lightness of Being in many ways reminds me of certain boys I remember from high school. They are pretty clever, but not as clever as they think they are. They throw around a lot of catchy ideas that, upon closer examination, lack depth and rigor. But the shallowness of their ideas is a feature, not a bug, in their popularity. Some of them are annoying, others not so much.
Many of the stuff in the novel are annoying, but some actually invite a deeper exploration (which the author did not do). One of the interesting ideas is the separate dictionaries used by Sabina and Franz, who are more caricatures than characters. Sabina represents the exiled intellectual from a former Communist country, i.e., Kundera's own uneasiness in France. Franz is a standup comedy version of intellectuals of the west --- It's funny, but also superficial and stupid.
Sharing some similarity with Kundera's situation but having emigrated at a much younger age, I happen to have a first-hand understanding of this "separate dictionary" phenomenon, except that I have a much better dictionary for the western culture than Kundera wrote for Franz. Sabina is a more precise portrayal, but his observation of the west, as represented by Franz, is largely cringeworthy.
I'm sure he wrote this part out of frustration with the French intellectuals who fawn over him without being able to understand him. On the other hand, he too failed to understand them. In his version, "the west" has the strength but lacks aggression. Franz is soft and unmanly. That's why he got dumped by Sabina and killed by some lowly Asian thugs. He is unable to arouse his women because he doesn't know how to issue a command "Strip" (in contrast with Tomas, an infinitely virile Czech man).
(One does not have to dig too deep for Kundera's metaphors.)
This characterization is extremely superficial and misses the reality by a long shot. But that's not surprising. Recently, I have been contemplating the impact of Communism on the 20th century history of the world. From time to time I am asked by American-born friends about the Communist regime of China, and every time I have to suppress an urge to give a longwinded answer about why the Chinese political system is only labeled "Communist", not unlike a box of fried chicken labeled as steak.
I have finally come to the realization that Communism, from the single source of Karl Marx's brain, morphed into a vast array of totally different meanings to different people who did different things with it. People assume they are talking about the same thing when they talk about Communism, but that's just an illusion. The theory of Communism did something to countries that label themselves as Communist or Socialist, including Soviet Union and China, but these are not really Communist things as defined by Marx. The theory also did something to countries that label themselves as Capitalist, but the effects are subtle and complex and requires some exploration.
To apply a bit of the systems theory, the fact that some countries in the world labeled themselves Communist (regardless of what they were actually doing) and happened to be economic and military rivals to some other countries in the world, caused those other countries to label any internal conflicts as Communist and foreign. For example, during the 1960s and 70s, the counterculture movement involving civil rights, women's rights, and gay rights was labeled as Communist infiltration by conservatives, thus rebranding long-term domestic conflicts as a foreign threat. When I first learned this phenomenon I almost laughed out loud. Obviously we are using different dictionaries in which the definitions of Communism has no resemblance to each other.