Losses or learning opportunities

I was chatting with Breevok the other day about gold 'stuff', expressing my jealousy at his gains in the 4.0 patch.  (I merely made a stuff load of gold - he made so much more).

He said something that struck me as odd.  "Don't worry - I made a loss over the last two days".  But did he make a loss, learn something, or merely add to his stockpile?

Regular AH players will make occasional losses.  Every time we buy something, there is the risk it won't sell, that we will be undercut by a new player/strategy or Blizzard will change the rules.  If you get it right you will make gold.  If you get it wrong you will lose gold.   (Just don't be this guy)

I am never happy with my gold making strategies, and am always tweaking them.  Read up on upcoming changes, observe the market. Do I have more/less time.  Am I accomplishing goals and/or burning out.  What can I change to make it better/easier/faster/richer?