I am a C# programmer, and this series by Eric Lippert really helped me to understand what the fuck a monad is: https://ericlippert.com/2013/02/21/monads-part-one/

It explicitly tries to answer the question: "I’m a C# programmer with no “functional programming” background whatsoever. What is this “monad” thing I keep hearing about, and what use is it to me?"