In this video, Motley Fool analyst Austin Smith has a message for investors: Don't get too comfortable with the current state of things. He reminds us that only a few months ago, the Dow (^DJI 0.77%) was way down and Apple (AAPL 0.53%) was at $700 per share. Now, Apple is tumbling, and the Dow is reaching historic highs. Austin tells us some of the factors behind these rises and falls and cautions against investing based on short-term market trends. He reminds us that the best way to invest is always to look at the fundamentals and make smart decisions about good companies -- whether the market likes them or not.