Every once in awhile this topic comes up in conversation or in a church sermon. The topic is that of how, "How are you?" is asked in a rushed way with the asker not really waiting for an answer.
My take on this is that "How are you?" is a meant to be taken as simply a greeting. Nothing more, nothing less. The asker probably ISN'T expecting a long drawn out response. The responder shouldn't be expecting to provide a long response.
Get over yourself, don't be offended if the asker keeps walking, and just take it as a greeting, like "hello". A simple "fine" response is really what both parties in the exchange are expecting/used to. Save the in-depth dialogue for a time when you're not passing each other in the hallway, etc. etc.
The asker isn't REALLY asking "how are you?" It's actually kinda a rhetorical question. No offense should be taken if a person doesn't stop to find out how you REALLY are every morning.