Some things everyone seems to know, but no one talks about. For example:

• Women leave toilet seats up; men leave them put down. This may be a genetic-code thing. We don’t know. What we do know is that if God intended us to leave toilet seats up he would never have let us invent them.

• Meter maids have ticket-writing quotas to meet, by the day, the week or month.

• The people who turn your lamp shades around in the middle of the night so that the seams show are the same ones who go into your dish of paper clips and link them up in pairs.

• When someone says “It’s not the money, it’s the principle,” you can be sure it’s the money.

• At the nation’s only birdbath for pterodactyls, in the center of Dupont Circle in Washington, D.C., there have been no sightings of pterodactyls, at least not recently. No one knows why.

• When rain is predicted and you take an umbrella to work, it doesn’t rain. When you don’t, it does.

• Shoelaces always break and staplers go empty at the wrong moment.

• When beleaguered politicians and other public officials resign under pressure, giving as their reason a desire to spend more time with their families, that is not the reason.

• The public figure who responds to an interview, debate or post-speech question with “That’s a good question,” would rather not answer the question and is worried that any answer will irritate someone in the audience.

• No matter how unprofitable they are or for how many years, Amtrak and the Postal Service will always conjure up one more restructuring plan with which to wring money or other concessions from Congress.

• When a politician says, “”It’s not a matter of politics, it’s a matter of conscience” — it’s a matter of politics.

• When you restart your computer after it crashes without warning, you will get a notice on the screen scolding you for failing to turn off the machine properly.

• Newspaper notices of subscription rate increases carry that information in the last paragraph, after several which inform you of the many wonders arising from your subscription.

• Telephonic Customer Service operators are always “busy assisting other customers”; however, “your call” is always “important to us.”

• Airport security screening is so cockeyed that those selected for “random” secondary searches will never fit the description of likely bombers or hijackers.

• At your computer, when you look for help in the “Frequently Asked Questions” sections of websites, no question you ask will ever be there.

• No matter how many times he fails to curb suicide bombers, Yassir Arafat will always be given one more “last chance.”

Peter Hannaford’s column appears every Monday.