Time for a bit of psychology ;)
This is known as proactive interference, where old information or actions (repeatedly saying 'hi, need' in a furni shop) interferes with new actions or information (answering the phone and saying 'hi, need' when its completely out of context)
Its a theory based on memory and although it doesnt happen often in short term memory it appears it has this time :P
Alternatively it could have been a subconcious slip of the mind from our good friend Sigmund Freud (Freudian Slip) :D
i lol'd though
