I agree about bitcoin for long-term investment. So, I think the key is to be patient and calm. New investors should know it. Panic selling at the lowest price is the only bad option.
Indeed, bitcoin was truly a long term investment because as you can see in the last few years bitcoin has only $600 when I'm started to earn bitcoin. In 2009 bitcoin was priceless and as the time goes passing by it became enormous. Those people who invest on that time will surely have a huge income.