I learned a few knots and even now when I buy a new pair of shoes I consult the site to see what lacing style would suit the shoe and my foot. (since different styles put different tension on the wearers foot).
I have to say, I'm happy it exists, it enriched my life in such a subtle way, this is the kind of content that the internet was made for in my opinion.
T-shirt folding. https://www.youtube.com/watch?v=b5AWQ5aBjgE
Gift wrapping. https://www.youtube.com/watch?v=1qi8ZXUH_wY