(Video of these slides here http://fsharpforfunandprofit.com/rop) (My response to "this is just Either" here: http://fsharpforfunandprofit.com/rop/#monads) Many examples in functional programming assume that you are always on the "happy path". But to create a robust real world application you must deal with validation, logging, network and service errors, and other annoyances. So, how do you handl