Getting in early on the next big thing always seems like a no-brainer in retrospect. The 1990s had dot-com companies. The 2000s had tech and social media upstarts. More recently, early Bitcoin investors are seeing returns that dwarf every other asset class. However, for every person who bought a Bitcoin at $10 and held onto it, there are thousands with tales of selling too soon, forgoing fortunes that might have been.