In real life, we often feel an impulse or a desire, and then act upon it with words or actions. For example… I’m feeling unloved and I want a kiss – so I ask you for one, or I bat my eyes seductively (why do people think eye-batting works… people just laugh at me). I feel tired and I want a cup of coffee – so I order one at Starbucks or brew a pot. You get the idea. Feeling results in impulse – creating words or actions.
In acting life, we are given the action or words and have to fill in the feelings and impulses.
Paul: Sally, would you grab me a cup of coffee?
… is what the writer gives us. We then have to choose the feeling: tired, thirsty, hungover or a million other possibilities. We also have to make the action: to “order”, “to plead”, “to demand”, “to charm” or a million other etc.. We are creating lives in reverse! We are given the tip of the iceberg, and must create the iceberg. The lovely side effect is that we are creating ourselves in the likeness of the character. As Ms. Stella Adler said “Character is defined through action”.
Please, please, please do not listen to the hacks that say the above line of dialogue is a “throwaway”. Most writers have labored countless hours over their work. They have ruthlessly hacked off any limbs that weren’t absolutely necessary. They have reduced a full life into two hours (or one hour for a TV series) and if it’s in the script – it’s there for a reason. Otherwise it would have been “thrown away” by the writer.
The reason that we want to create our lives in reverse when we act, is so that the structure is firm enough that we no longer have to think about it. When it comes time to perform – we can let go and fly. Any magician knows that it takes time to create the illusion of magic. We want it to look easy to the audience. Unfortunately, many actors think it is just easy. And that, my friends, is why people watch reality TV.
Jeffrey Marcus Acting Class 
I like this one!
I’ve always thought of the “throw it away” line to mean this:
If you’re a waiter and come up to the table and say “here’s your coffee”, don’t make a meal out of a mouthful. It’s a “throwaway”, meaning the scene is not about you coming up to deliver the coffee, the story needs to move along with it’s inherent pacing.
Yes, of course, you need to make choices about whether you’re a happy/disgruntled/tired/perky/annoyed waiter….but let’s keep the story moving along.
Well said!
Just watch any couple at a bar or coffee shop or wherever (someone you don’t know works best) and it is striking how such simple requests reveal the relationship. Did they just have a fight, are in a hurry, are they annoyed that they’re even asking! All of it seems to pass between them.