Sublime text and the vim extension vim-gutentags (
https://github.com/ludovicchabant/vim-gutentags) allow you to open projects and immediately go to symbol definitions and references without any configuration or setup. They also handle background indexing as you work.
It would be very nice if Emacs had an option to work the same way, where I could open a project and immediately navigate symbols built from the project.el root, without having to manually futz around with tags.