Some of these are esoteric keyboard shortcuts for things that are possible to do in a less-undiscoverable way. Others, like right-clicking on the trackpad and s

Some of these are esoteric keyboard shortcuts for things that are possible to do in a less-undiscoverable way. Others, like right-clicking on the trackpad and scrolling without a visible scroll bar very quickly become second-nature when you start using a Mac, because it's impossible to navigate otherwise. Only the "Open With" case is really valid, because even the non-keyboard way of doing it (again, not mentioned in the article) is really fairly esoteric: [right-click] > "Get Info" > [select application for this file] > "Change All..." to apply to all files with this extension.