This is my last post in this thread. May the force be with you.
Say, you want to send a letter (HTTP request) to Helen in Paris, France via a train. You have to know:
[list]
[] The right address (Paris, France). In this case, the right action.
[] The right name (Helen). In this case, the right name.
[] The right method (by train). In this case, the right method.
[] The right content (what you want to say and what she expects to read). In this case, the right value.
[/list]
If one is wrong, everything will get messed up.