Sports have unwritten rules. In baseball, jogging slowly around the bases after hitting a home run, or stealing second with a 10-run lead, or cutting across the pitcher's mound on your way to the dugout are all violations. Breaking one can lead to bean balls and empty dugouts. Punishment is often swift and harsh.
A colleague proposes an idea. It stinks. Not your job to say so, though. If you're a supervisor and another supervisor makes a terrible suggestion that doesn't affect your area or your employees, sit tight. Let someone else, preferably someone above you, shoot it down. Then jump in if you can to modify the idea so it is more workable, giving credit to the other supervisor for raising an important issue, of course. Bad ideas come and go, but professional relationships should be forever.
You walk into a conference room. The CEO, fresh off the plane, is there. Say hi, introduce yourself, and then sit at least two seats away. There are better ways to get face time. Plopping yourself down by the big guy (or gal) will do nothing for your career and everything to draw sideways glances and post-meeting sniping.
You have a mentor. Great! Mentors can provide motivation, be a source of ideas, provide counsel and guidance. So pass it on. Mentor someone below you. Otherwise everyone knows you take like a bandit but give like a miser. Think of it this way: You may aspire to someone's position, but at the same time someone aspires to yours. A sub-set of this rule: If you want a great mentor, first be a great mentor.
We all like sharing good news. Good news is interesting; bad news is critical. I like to know a shipment went out on time, but I need to know a shipment will be late so I can contact the customer and put other plans in place. (And speaking of customers, always share potential negatives as soon as possible — the fewer surprises the better.) Positives are easy to deal with; negatives can make or break a business if the right people are not aware.
We've all known the guy who must speak in every meeting, even if he has nothing to add. (Okay, we've all known a lot of those guys.) You may think you need to contribute just to show you're involved; the rest of us know you're just talking to show you're important. And we think a lot less of you as a result. Think of words as something scarce; use them sparingly and only when they will make the most impact.