My pet peeve with TypeScript and React isn't with React but some parts of the ecosystem, like redux-saga: there are subtle issues with using the saga operators that mean that although the compiler makes it look like type inference is working, you've actually lost the type being ``taken`` from redux with redux-saga. To maintain type safety, you need to do funny things like "typeof sagaFunction".

Little things like this can add up to subtle bugs and tech debt if you're not careful.