I think, sleeping over the investments. Yes, this is how the most amount of money can be made if you are a real long-term investor in publicly listed companies. Finding opportunities is not easy. There are over 1600+ companies listed on the National Stock Exchange. But once you find a good company and decide to invest your savings in it. It is important to be bold and stop thinking about it everyday. If you start to become fickle and cross-question your rationale every now and then, then you will sell your stocks too early and miss out on the steady capital appreciation over the years.