When I first started out, my friend Morgenstern was general counsel of our division. One day he saw me walking down the hall with a magazine, reading. He took me into his office and put an avuncular arm on my shoulder. “Don’t walk around with reading material,” he said to me. “At best, people will think your head isn’t in the game. At worst, they’ll think you’re on your way to the restroom.” Today there are two of us from the old division still standing — me and Morgenstern.

Not long thereafter, I took to wearing red suspenders. I thought they gave me business credibility. One day I was in the office of the president of our Large Rotating Objects group, whose name was Goodfellow. He wasn’t one, but that’s another story. He looked up and said, “What the hell are you dressed as? A banker?” Then he adjusted his toupee. That night I threw out my suspenders. The next day I wore brown. Today I seldom wear a tie, except when I’m trying to pass as somebody with financial literacy. When I look in the mirror, I recognize myself.

In the mid-1990s we had a CEO I liked. One year I got him a birthday present. Possibly an exploding golf ball, I can’t remember. The next day I received a note, written on a disposable company buck slip. “Thanks for your stupid gift,” it said, “but you’re wasting your affection on the wrong person. Sid.” I appreciated the advice. Since then I never expend affection on the wrong person, no matter how tempting it may be organizationally.

A couple of years later I was in New Orleans for a convention. It was 3 a.m., and there weren’t many people left on Bourbon Street. “Let’s get a nightcap!” my friend Moran was yelling, tilting slightly to and fro. A voice inside my head said, “Don’t do it.” So I went back to the hotel. The next morning Moran was still missing. I made the early meeting, although I snored several times. When that little voice declares itself, I always listen.

I also appreciate the advice given to me by Mrs. Garino, my second-grade teacher back in Illinois, where I almost remember growing up. “Stanley,” she told me, “don’t be afraid to ask a stupid question. It may not be as stupid as you think.” I have found, during the course of perhaps 10 million meetings dedicated to economic matters, that more than half the table does not really understand what the other half is talking about. Many of the clueless are ultra-senior managers. Given how many stupid decisions have been made by smart people recently, I generally ask whatever stupid thing comes into my mind, even if a majority of people around the table are nodding sagely. Sage nodding conceals a multitude of sins.

Beyond that? Stuff that sounds better than it is: Keep your friends close and your enemies closer, for instance. Seems good, but then you have to hang around with your enemies all the time. Don’t bother that bee and it won’t bother you? As if. Bees are like MBAs. I can’t tell you how many have stung me when I was minding my own business. I know! Buy low, sell high. Great advice! The trouble is, it should come with reliable suggestions on proper execution, which it doesn’t. So most of the time I end up doing the opposite.

Wait, I’ve got it. Do unto others. Best advice of all. Timeless. Easily achieved. Something you can live by every day. I think there was a bit more to it, but for some reason I can’t remember what it was right now.

Follow Stanley Bing at stanleybing.com and on Twitter at @thebingblog.

This story is from the November 18, 2013 issue of Fortune.