This has to be one of my favorites of all the episodes, and one near and dear to my heart.  Dogs, like people can have mental illness, severe moods, mental and emotional issues.  They aren't exactly like us, but they can be similar in the variability in how they perceive their world.  When we interact with them, whether in training or regular life, if we first take into account "where their head is" and what they are thinking, or not thinking about, EVERYTHING is immeasurably easier.  Here is some food for thought in working with and owning these canines...