First and the most common is that they will not do their due diligence or do they own research. Because that is also how I hustle when I was new to trading and every altcoin projects reach their moon so I thought to myself that since it can happen to any coin then I will just listen to the most people who shilled the same coins and will buy it. Not gonna lie that it worked but everything now has changed. You need research and please do not put your money on projects that has only beautiful whitepaper.