> Domino effect: one bug can take down the entire system at once

It bothers me that this is always set as a selling point for microservices, when it's actually the opposite. With monoliths (or at least monorepo) it's easier to test complex flows. When you split into microservices, they are still there, but there are so many boundaries in development that you end up testing in prod. For me it's a bit like unit tests vs integration tests. It means to naively think that all those unit tests somehow interact together to define the functionality that you want