It took the author of RxJava months to understand the concepts. And he had the author of Rx.Net to explain them to him [1]
It's also strange is that what we realy want is Excel-like reativity. But instead we're always getting Rx-like reactivity.
[1] From his book: https://pbs.twimg.com/media/C0M-U1DXcAADTS3?format=jpg&name=...