The vacuum Won't Start

A retired guy sits around the house all day so one day his wife says, "Joe, you could do something useful, like vacuum the house once a week". 

 The guy gives it a moment's thought and says, "Sure why not. Where's the vacuum?"

Half an hour later, the guy comes into the kitchen to get some coffee. His wife says, "I didn't hear the vacuum running,  I thought you were going to do the vacuuming"?

Exasperated, Joe answers, "The stupid thing is broken, it won't start. We need to buy a new one".

 "Really", she says, "Show me - it worked fine the last time".   So he did.