Quick Takes . . . . Always wondered why I didn't go into retailing, and now I know . . . . Had dinner a few nights back with a friend who works as a salesperson at a snazzatorium near White Flint . . . . She says she often spends many hours with a customer, spread over several days, before a sale is made. But when it comes time to write up that sale, my pal is sometimes not there. So someone else fills out the sales slip . . . . Even so, the person who spent the time and did the selling ought to get credit for (and the commission for) the sale, no? . . . . Unfortunately, no. My friend says her boss and coworkers routinely put their own computer numbers on the sales slip, assuring that the commission goes into their pockets . . . . Rotten? Certainly. Fraudulent? I'm no lawyer, but I'll bet it is . . . .

Don't know why you'd ever want to do something like this, but if the urge strikes you, here's fair warning . . . . Carl Coleman of Fairfax was out in San Francisco, and he discovered he had a Metrorail farecard with him. So just for kicks, he tried to use it to enter BART, the S.F. rapid rail system . . . . All Carl got for his trouble was "SEE ATTENDANT." Would a BART farecard work any better in Metro's turnstiles? Carl bought a BARTcard, and tried it when he got home . . . . "TRANSACTION CANCELLED. SEE ATTENDANT," was the result . . . . All of which proves two things: 1) You can't fool a computer on either coast, and 2) Like Washington humans, Washington computers can't resist using four words where two would do . . . .

Speaking of computers, the one belonging to the Parking Violations Bureau of the City of New York could use some new batteries . . . . Tricia Noone of Cheverly recently got a letter swearing that she owed the Big Apple $890 for unpaid parking violations incurred in 1980 . . . . The New York computer decided that Tricia owed this money because her Maryland tags now read HBL415, as did the tags of the illegally parked car in 1980 . . . . Only trouble is, Tricia was 15 years old in 1980, didn't obtain a driver's license until 1982, and wasn't issued HBL415 until 1983 . . . . Of course, Tricia well knows that The Truth is often what a computer says it is. So she has demanded assurance, in writing, that "should I ever visit New York, I would not be treated like a criminal" . . . . Has the N.Y. computer answered Tricia yet? Dream on, you sweet thing . . . .

Clever twist on an old problem . . . . Paul B. Jacoby of Chevy Chase says that, rather than ticket nonhandicapped motorists who park in handicapped-only spaces, we should require them to give a week of volunteer time to an organization such as Special Olympics or Disabled American Veterans. "The fine only lightens the wallet; the service might raise the level of a conscience," writes Paul, ringingly . . . .

Apocryphal, no doubt, but funny, no doubt either . . . . Bill Sullivan says he knows a Secret Service agent who recently busted a counterfeiter . . . . According to Bill, the bad guy said this to the good as the latter was applying the handcuffs: "I make money the old-fashioned way. I print it!" . . . .

Congrats to the Silver Spring Kiwanis Club, 37 years old as of last month . . . . Hisses to WDCA-TV (Channel 20), for Egregious English. Cynthia Laing Fern of Chevy Chase was watching a movie on that station not long ago when this warning appeared: "Viewer Disgression Advised." Dictionary Use Advised, too, gang . . . . And who out there would like to earn money while helping to find new remedies for high blood pressure? George Washington University Hospital is looking for HBP sufferers who will take part in a new study. Further info: 676-4248 . . . .

'Twas the day after Christmas, and a Fairfax couple was browsing through Georgetown . . . . They saw a wall unit on sale in a furniture store, and they bought it on the spot . . . . But when it was delivered the next day, it turned out that the Grinch hadn't stolen Christmas. He had stolen two knobs off one of the drawers . . . . For nearly four months, the she of the Fairfax couple has been trying to get the knobs replaced and delivered . . . . She has encountered every duck known to mankind . . . . "Sorry, but the manager has just stepped out of the office." . . . . "You'll have those knobs by next week." . . . . "I'm sorry, but the general manager is in Pittsburgh." . . . . Moral of the story: look at what's delivered before the truck departs, so that you can refuse to take delivery if necessary . . . . As this story proves, if A Little Something is wrong, refusing the merchandise may be the most effective protection you have . . . .

And finally . . . Jim Reiter of Crofton was driving through Bowie the other day, when what should he spy? A car at the side of the road, into which a motorist was pouring gas from a five-gallon can. It was the kind of can you walk to a gas station to get and fill when your buggy runs out of fuel . . . . Of course, the vanity tags on the out-of-gas car read: PLAN . . . .