even the best possible investors can't make guaranteed profits. thing to keep in mind is that when you depend on others, and that's exactly the case with trading and whatever form of investments, there will always be uncertainties. you simply don't know what others will do. right now can be all fine, but what about tomorrow? and exactly these uncertainties are something that no one can predict/see. but at the same time, that's also why people get attracted to invest instead of saving. it's exciting, there is potentially a decent sum of money to be made, you feel like you're doing something good, etc. it's a combination of everything.