OK, those agents suck. The homeowner is never supposed to be home during an open house and preferably not even during a showing.
I will never forget the house scouting trip we made a year before we moved back to MA. We saw: houses with unflushed toilets and underwear strewn around, houses with ironing boards set up in the family room, houses that were 200K over our price range with no central AC, on a 95 degree day, and finally, a house where when my DH went to go up the back steps to the deck, he fell through the step! Oh, and then there was the house where the garage door fell off as the agent was raising it... This was during the "boom" of the late 80s. People were selling houses for way more than the list price and the condition didn't matter at all. Of course, a year later, when we moved, things were quite different.
No wonder so many houses don't sell!