Edit: You don't really need monads any more than you need classes, interfaces, functions, procedures (just use goto!), etc. they just help bring a bunch of seemingly disparate functionality together into one standard (which is helpful in, e.g. Scala or Haskell where there's some syntactic sugar for dealing with monads). People complained for the longest time (amongst many, many other things) that Javascript lacked classes, even though you could totally hack it together with `new`, functions and prototypes. Similarly, FP people complain that everything else lacks monad support, even though they can hack it together with largely language independent features (typically without compile-time checking).

I don't have an intuitive grasp of the formal definition of monads, but some examples of things that I _think_ are monads (in Java ... sorry :/ it's all I work with these days):

* jOOQ [1]: you use it to build up a sequence of SQL statements with a pleasant chaining API, then execute the whole shebang * Promise/future chaining: you build up a sequence of promises that should apply in-order, then defer their execution until later (unless you use a language that performs a transformation at compile time which effectively does this for you). * Streams/optional mapping: you build up a sequence of functions that should apply in-order to every element in a potentially empty sequence (optional: a sequence of 0 or 1). * The builder pattern: you build up a sequence of property values, then (potentially) construct the entire object.

[1]: https://www.jooq.org/