The Wikipedia article on monads says:
Purely functional programs can use monads to structure procedures that include sequenced operations like those found in structured programming.
Not looking for an (another) monad tutorial here. Just please give an example of monad making sequenced operations possible when just running one function and then another is not enough. Is it somehow connected with those function calls being lazy per functional language specifications? Why sequential run of not-interchanged functions needs any "wrapper"?