I skimmed the article. I began to get anxiety once I realized how long it was. JavaScript is a very simple language. `this` in JavaScript is easy to understand. Long posts like this give me anxiety.
It's like an exhaustive, confusing list of examples rather than explaining briefly the very simple and largely intuitive reasons that lead to these examples.
I'm reasonably smart, but I don't ever remember the various contextual meanings of "this". Maybe because when I use javascript I try to use frameworks that hide the need to think about it. It's a wart on the language in my opinion.