When the stock market has a big day – up or down – it often makes perfect sense. A hurricane strikes. War breaks out. Inflation jumps. …

Other times, the market’s big moves leave a lot of us scratching our heads. Take the leap on June 29. All the experts said it was a reaction to the Federal Reserve’s new policy statement on interest rates. But what did the Fed say?

That future decisions about whether to raise rates further “will depend on the evolution and the outlook for both inflation and economic growth.”

Isn’t that always so? Yes, but investors apparently were overjoyed that the statement seemed to open the door for the possibility that the recent quarter of a percentage point increase might be the last. Or maybe the second-to-last.

Stocks soared around the world, reversing many of the horrible losses suffered during the spring. Gee whiz, Wall Street. One minute the sky is falling, the next you’re a bunch of drunken sailors buying everything in sight.

Let’s jump on the bandwagon and assume the Fed is done raising rates. So what?

The first lesson to take from the past few months concerns foreign stocks, which long have been seen as a way for Americans to diversify – to spread risk around. Since foreign stocks march to their own drummers, the hope was that when U.S. stocks were down, your foreign ones would be up.

But in recent years foreign stocks have tended to move in the same direction as U.S. stocks, but to greater extremes. So instead of softening the volatility in your portfolio, they amplify it.

This is due to the growing interconnection of economic and financial markets. When the risk of inflation and higher interest rates appeared to rise this spring, investors wanted to reduce risk, so they dumped foreign stocks, driving prices down.

The lesson isn’t that we should avoid foreign stocks, but that we should steel ourselves to a very rough ride – not just now and then, but always.

Next, if interest rates are now at a peak, it could affect some investment decisions.

Stocks are more attractive when interest rates are flat or falling. “Rising rates increase borrowing costs for consumers and businesses, cutting into buying and hurting corporate profits, which is bad for stocks. Falling rates do the opposite.

Next, what about mortgages? With the risk of an interest-rate spike apparently abating, you can probably take your time shopping around. You can still get a 30-year, fixed-rate loan for 7 percent or less, which is pretty good.

As I said, all this assumes the Fed is done raising rates. All bets are off if some new inflation statistic throws the markets into a tizzy. And investors’ obsession with interest rates may just give way to a new obsession with corporate-earnings reports.

It would take only a few disappointments for the markets to lose all the enthusiasm. For us small fry, the best strategy may be to sit back, ignore the market’s short-term ups and downs, and just enjoy the summer.