I love the advocacy for a custom-less setup given here. Mind you, I have no desire to go without the customization family of helper commands like customize-group and customize-variable: the ability to rapidly explore the options available for plugins, libraries, and styles feels like a “killer feature”. But as software engineering has grown over the decades we are in a place to better understand the values in locating those customization in the same place where they can be associated, shared, and simultaneously deleted/edited.

If you work much with the Orgmode agenda you soon find that you can have a huge amount of appointments and todo tasks to deal with. You can sort these by putting tags on the, either straight from the agenda view (with :) or in the actual org file (with C-c while point is over a headline). You can then use those tags to filter and search your agenda (from agenda view, with / and \ followed by TAB).