[pjc50]

You can go a very long way in programming without ever needing to explicitly use a monad for anything. The usual route into needing them is something like Haskell's IO: if you want as much as possible of your code to be stateless and immutable, how do you deal with IO, which inherently changes state external to the program?

If you've learned from the assembly end of programming upwards, it can be very hard to see the need for them at all.

[james_s_tayler]

You can go a very long way in programming without realising you inadvertently have been using Monad's present in the language/standard library :P