I think you are misunderstanding the term “efficient” as it applies to markets.
An efficient market is one where the price fluctuates to ensure that supply and demand are always equal. The extent to which supply and demand are not equal is the extent to which the market is inefficient.
With this definition in mind, I can’t think of any markets that are more efficient than the publicly traded stocks and commodities market.
Just because you don’t understand the supply and demand side of the stock market (i.e. who wants what when, and how much are they willing to pay, and who wants to sell when and how much they want) doesn’t mean the market is inefficient.
Efficiency isn’t a function of buyers’ preferences, just the price adjustment.
Granted, though, the stock market can be confusing.
