There's not much underlying gold's value (there are some industrial uses and there's the public's love of gold for things like jewelry, but those intrinsic values aren't what have been driving gold prices for the most part). It's all about perception and what people want to believe, and such things can be fickle. That makes gold quite momentum-dependent and highly unpredictable.
Gold is the preferred medium of exchange (money) in a free market. Over generations of market trial and error, it was determined to be so because of its scarcity, durability, divisibility, and stable natural supply.
Today, governments have decreed pieces of paper with ink on them to be "money." As such, we no longer have a free market. We have a few central planners who think they can control the market: millions of human interactions.
When analyzing gold as an "investment", it should be compared to the fiat currencies of the world, not stocks and bonds as many try to do to. With that I ask you, what is the intrinsic value of a Fedeal Reserve Note? It is nothing more than an instrument of debt, as it is loaned into existence at the will of central bankers. Any number can be put on a Federal Reserve Note, whether it be one or one-trillion, and it requires the same amount of labor. That is not intrinsic value. Mining one trillion ounces of gold takes a far greater amout of labor than one ounce; now that is intrinsic value.
Contrary to what you say, it is actually fiat currencies that are all about perception and what people want to believe. We are living inside a debt-based fiat bubble right now, and it is hard for people to see outside of it. Eventually, it will end and you would be wise to own some sound money.