React Native, a popular framework for building mobile applications, has gained significant attention and adoption in the software development community. However, like any technology, it is not without its shortcomings, which can lead to disappointment for some users. Here are a few reasons why some people may be disappointed by React Native:

1. Performance: React Native relies on a bridge that connects the JavaScript code to the native components of the mobile platform. This bridge can introduce some performance overhead, especially for computationally intensive or graphics-heavy applications. While React Native has made improvements over time, it may not match the raw performance of fully native applications.

2. Native UI limitations: React Native allows developers to build user interfaces using components that map to native UI elements. However, there are cases where certain native UI components or features may not be readily available or fully supported in React Native. This limitation can result in additional development efforts or compromises in the user experience.

3. Platform-specific issues: React Native aims to provide a cross-platform development experience, enabling developers to write code once and deploy it on multiple platforms. However, due to differences in the underlying platforms (iOS and Android), developers may encounter platform-specific issues or inconsistencies. This can lead to frustration and additional debugging and maintenance efforts.

4. Ecosystem and third-party libraries: While React Native has a vibrant ecosystem and community support, it may not always offer the same breadth and depth of third-party libraries and tools available in fully native development. Some developers may find that certain libraries they require are either not available or lack the same level of maturity and stability as their native counterparts.

5. Upgrades and maintenance: React Native evolves rapidly, introducing new features and improvements. However, this can sometimes lead to challenges when upgrading existing projects to newer versions. As breaking changes are introduced, developers may need to invest time and effort in adapting their codebase, which can be frustrating, especially for larger or more complex applications.

It's important to note that while some people may experience disappointment or challenges with React Native, many others continue to find it a valuable and efficient framework for mobile app development. The choice of technology ultimately depends on various factors, including project requirements, team expertise, and individual preferences.