Already in the green.

I just saw something that surprised me in an article in The Atlantic:

"Anyone who sold their stocks when the crisis climaxed in the fall of 2008 would already be back in the green if they had held on."

I watched so many people sell off right after the crash. On occasion I tried to argue with them. What part of buy low, sell high don't these people understand?

Of course, I was arguing that early 2008 was a good time to be buying stocks. So I probably have been following more of a buy high, buy low, pretend you are going to sell in a few decades and everything will go up strategy. This seems justified to me though, at my age it would have been a good strategy for most of the past hundred years. Still as many people have pointed out to me, there is the chance this next century will be much different than the last. There is no fundamental reason stocks should always go up.