"Markets often rise higher than you think is possible, and fall lower than you can possibly imagine" a quote from Jim Rogers . A very powerful market tool to remember.

Jim Rogers' quote has made me alot of money. But this year, my biggest mistake was forgetting the other half of the quote: Markets can fall lower than you can possibly imagine.
Banks and homebuilders – two things I believe are cheap and hated – have fallen lower than I could have possibly imagined. I bought in too early. I thought I saw a glimmer of an uptrend. So far I've been wrong. Jim's rule was right, as always. So right now, I'm watching my trailing stops closely on these.
If you want to make a whole lot of money investing, you have to stick to your rules. Jim Rogers' rule is one of the most difficult to stick with... but it is one of the most profitable.
Oil moving up 900% is a great example of the market rising higher than you think possible. And financial stocks and housing, unfortunately, are a good example on the downside.

Markets often rise higher than you think is possible, and fall lower than you can possibly imagine."
This rule will make you a lot of money. And both halves of the rule are equally important.