A very concise book

We recently created a very tiny book on philosophy, possibly the absolute smallest of its kind. It's around a 5 minute read.
Please don't mind the informal language, as the book was written like that to save space and for ease of reading.
It's written in markdown, so you may want to convert it to html, but you can also open it on a text editor, although it won't look as flashy.
Feedback would really be appreciated.