• It is amazing to me following the whole Wal-Mart (search) mess these days. I kept wondering, what the heck happened here? A company now on the offensive after years of attacks.

    I can remember many years ago, back in the early 1980s, interviewing Sam Walton himself. Back then Wal-Mart was just gaining cult status. It could do no wrong. Sam was the man.

    That was then. This is now.

    It happens in business and life all the time.

    Last year, Continental Airlines (search) was flying high — the envy of the industry. Now it's desperately looking for worker pay concessions just like everybody else in the industry. Costs too high — stock buyers too few.

    I remember when Franklin Raines (search) at mortgage giant Fannie Mae could do no wrong. Now he's out of a job and Fannie Mae is out of excuses.

    It goes the other way too. Wasn't too long ago that Apple Computer (search) was given up for dead. Then along came the IPod. It's cool and Apple's stock is cooler.

    Reminders all that if you wait around long enough, dogs become darlings and darlings become dogs. Back and forth, on and on.

    Snapshots in time — only for a time.

    The moral of the story: assume nothing is permanent and stay humble because you've assumed right.

    Watch Neil Cavuto weekdays at 4 p.m. ET on "Your World with Cavuto" and send your comments to cavuto@foxnews.com