Most first-time investors and gamblers seem to focus on high beta stocks or markets, such as oil prospecting companies or the Russian stock market. In the article in the link below there is an explanation why there may be a negative downside to this besides just higher volatility.
[...] People who bet on horse races bet on the long-shot horses more than would be justified by the actual odds of winning (and conversely bet less than they should on the favorite horses). The story generally goes like this: Horse-racing bettors have difficulty evaluating small differences in outcome probabilities, for example the difference between a 1-in-50 odds horse and a 1-in-100 odds horse. That’s a 2% probability of winning versus a 1% probability of winning. This results in a large proportion of bettors placing too high of a bet on the longer odds because the potential winnings appear larger in that case.
The logic behind this behavior is most likely applicable to other markets of uncertainty such as the stock market.