The 'fatal: the remote end hung up unexpectedly' error during a push operation to GitHub is commonly seen when trying to upload large files or a large number of files, exceeding GitHub's size limits or causing the connection to drop. GitHub has a file size limit of 100MB per file and a total push size limit of around 1GB. If your push exceeds these limits, consider using Git Large File Storage (LFS), a tool specifically for tracking large files such as media or binaries in Git. Git LFS replaces large files with text pointers inside Git, while the actual file is stored on a separate server, effectively managing your repository size. Install Git LFS, track your large files (e.g., `git lfs track "*.psd"` for all Photoshop files), and then push again. Alternatively, if you're pushing a large number of files, try splitting your commits into smaller parts to avoid overloading the connection. Following these steps typically resolves the 'remote end hung up unexpectedly' error, allowing a smooth push.