You should get greedy when others are fearful and fearful when others greedy. Of course, you shouldn't get greedy when others get greedy and fearful when others get fearful.
别人恐惧时你该贪婪,别人贪婪时你该恐惧。当然,别人贪婪时你不该贪婪,别人恐惧时你不该恐惧。
─沃伦·巴菲特(Warren Buffett,美国著名投资家)