A quick search will find plenty of references for the classic Brooks quote:
Show me your flowchart and conceal your tables and I shall continue to be mystified. Show me your tables and I won't usually need your flowchart, it'll be obvious.
I think substituting 'messages' for 'tables' preserves the meaning while bringing it forward into what seems to becoming a service-driven era. Guy Steele did something similar a few years ago, except specifying object interfaces instead. Too much coupling, messages work better :-)