I've assisted several large clients in building a microservices-style architecture using Kafka as a messaging backbone, having a reasonably good understanding of its abilities and the use cases that really bring them out. But I'm not a Kafka apologist by any stretch; any technology that has gone through such a rapid adoption curve is bound to polarise its audience and rub certain developers up a wrong way, and Kafka is no exception. Like anything else, you need to invest a significant amount of time in getting across Kafka and event streaming in general, before you become fully proficient and can harness its might. And be prepared to face one or two frustrations, to put it mildly, along the way.
I've compiled a list of shortcomings that may cause developer frustration, or catch out unsuspecting first-timers. In no particular order: