What problem does Docker primarily aim to address?

Docker primarily aims to address the issue of applications working inconsistently across different environments, which is encapsulated in the concept of "works on my machine." This problem arises when software behaves differently on different machines due to variations in operating systems, libraries, configurations, or underlying infrastructure. Docker solves this by providing a standardized unit of software, called a container, which packages an application along with its dependencies and environment. This ensures that the application runs the same way regardless of where it is deployed, be it a developer's local machine, a testing server, or a production environment.

By using Docker, developers can create, manage, and deploy applications without worrying about the inconsistencies that may arise from different environments. This capability greatly enhances the efficiency of development and deployment processes, as applications can be reliably moved between different environments without encountering the compatibility issues that often arise in traditional application deployment.