Over time I’ve come to appreciate that feature of the iMac that asks its users, “Are you sure you want to permanently erase the items in the Trash?”

To underline the importance of this question, the iMac adds this reminder: “You can’t undo this action.”

I’ve been using Macs long enough to know the consequences of the action. That’s why the computer’s nagging inquiry occasionally annoys me, usually when I’m in the grips of a frenzy brought on by a mess of files that seem to have created themselves . . . for no reason that I can recall. So into the trash they go!

Then comes the question . . . and the reminder (which treats Trash as a proper noun).

IN FAIRNESS, I admit this reminder sometimes prevents mistakes. Unfortunately, more times than not, my trash reflex is quicker than my brain and — ooops! — items are erased before I’ve reconsidered.

But the subject here is not the trash reflex; it’s that other thing — the brain: Wouldn’t it be nice if it alerted us when certain things in our memory bank were about to be forgotten . . . and did we wish to prevent this?

But no, the brain arbitrarily erases items all the time . . . like where did we hide all of those passwords we’ve been forced to create since we entered the computer age? Or what's the date of our wedding anniversary? And why am I standing in front of the refrigerator?

MOST AT RISK are words seldom used. Since I was never much interested in cars, there’s a whole vocabulary my brain may have put in a foreign language file — words such as “alternator,” “carburetor,” “voltage regulator,” “camshaft,” “distributor,” “differential” and “intake manifold.” I had to look them up in a thesaurus while writing this piece.

God’s solution, obviously, was the creation of the word “thing,” which the brain never forgets. Indeed, in an emergency, it’s the first word the brain sends you. As in, “All I know is my car won’t start. It must be because the thing is broken . . . you know, that thing that turns the car on. Maybe all I need is a new thing.”

I figure the brain has to dump a load of words, names, dates and telephone numbers whenever it approaches an information overload.

I’m frequently reminded of that scene in the entertaining Cary Grant-Audrey Hepburn movie “Charade,” when Grant’s character tries to make the acquaintance of Hepburn’s Regina Lampert. But she turns him away with the film’s most-quoted line: “I already know an awful lot of people and until one of them dies I couldn’t possibly meet anyone else.”

(To which he replies, “Well, if anyone goes on the critical list, let me know.”)

AND SO it must be that our brains cannot process new data until it discards some of the old. Perhaps that’s why I’ve always had trouble remembering names, especially of people I meet at social gatherings. My brain knows I won’t see most of these folks again, so why bother storing their names?

The mystery is why the brain retains so much useless information — like why I remember a singer named Jo Anne Greer recorded a song called "Forty Cups of Coffee" back in the 1950s, that a teenage actress named Denise Nickerson was freaky good in a 1971 TV movie called "The Neon Ceiling", or that in 1951 an outfielder named Frank Saucier was considered a sure bet for major league stardom. (He played 18 games for the St. Louis Browns that year, then was recalled by the Navy for active duty during the Korean War, and never played another professional baseball game.)

In the meantime, my brains continues to mess with me without permission. If you'll excuse me, I've got to go to the kitchen. But when I get there I won't remember why.