The feature that I like most in a wordpress admin dashboard is wordpress custom menu. A custom menu can replace default menu bar or navigation bar easily and enables a user to show pages, categories and also external links in the same menu-bar. 
To do this a person don't need to know a single line of html or css. Simpley go to Menus under Appearence.Create the first menu from the right side option.After that select the pages and posts in orted to add to menu. While add any external page, edit the custom links option at the top, put URL and Lebel, and then add to menu. It's so simple!
But the reason behind popularity of wordpress custom menu feature is, anyone can create enough custom menus to show as widgets easily. Thus, you can select similer pages, posts or link to put on each menus.