AngularJS is an open-source JavaScript framework designed to simplify the development and testing of single-page applications by providing a model–view–viewmodel (MVVM) and model–view–controller (MVC) architecture. Despite its popularity and robust feature set, developers often make common mistakes that hinder the full utilization of AngularJS's capabilities. These errors include failing to keep track of watchers, improper compartmentalization of code, over-reliance on jQuery, improper use of event handlers, neglecting testing, and not utilizing available debugging tools like Batarang. Developers also often make errors such as direct DOM manipulation, not using $applyAsync, and declaring components in multiple NgModules, all of which can degrade application performance and maintainability. By addressing these issues and learning from the mistakes of others, developers can enhance their AngularJS applications' scalability and reliability, benefiting from the extensive support and resources available due to AngularJS's backing by Google.