Horseplayers get themselves in trouble when they develop passionate likes and dislikes for particular horses. We lose our objectivity, our ability to analyze races open-mindedly.

I am an expert on this pitfall. A few years ago I wrote so often that Seattle Slew was an overrated mediocrity that I never was able to bet him or appreciate him, even when he went on to become the most valuable thoroughbred in the history of the species. Conversely, I fell in love with a colt named Star Gallant and kept thinking he was going to wind up in the Hall of Fame, even when he wound up losing such races as the Chief Pennekeck Handicap.

So I should be forewarned. But after Proud Truth rallied to win the Florida Derby on Saturday and was widely heralded as the horse to beat in the Kentucky Derby, I can't suppress my feelings.

I hate Proud Truth. If he had been born into even a fair-to- middling equine generation, he would have been a nonentity, but even in this bad year I think his mediocrity soon will be exposed.

To be fair, Proud Truth does possess a certain amount of character. He prevailed in a long stretch duel when he defeated Stephan's Odyssey in the Fountain of Youth Stakes. He overcame some trouble in the Florida Derby, and when jockey Jorge Velasquez got him out of tight quarters, he accelerated powerfully in the final yards to beat Irish Sur. Proud Truth is a consistent colt, too. He's won five of his six career starts and never turned in a bad effort.

I, too, was a gritty competitor with character when I was a runner, but no rational person would have bet on me in the New York City Marathon. Character goes only so far if you're slow. And the times of Proud Truth's races suggest that he has been able to look good only because the 3-year-old stakes competition here has been so weak.

The track at Gulfstream Park was almost precisely as fast on Saturday as it was for the Florida Derby a year ago, when Swale beat Dr. Carter. Swale ran in 1:47 3/5. Proud Truth ran in 1:50, which means he would have been beaten by a dozen lengths if he had faced last year's good 3-year-old crop.

He didn't even run well enough to have beaten Croeso, the long-since-forgotten winner of the 1983 Florida Derby. The slowness of that performance was not a fluke; Proud Truth's times in the Fountain of Youth and the Tropical Park Derby were comparably weak.

Many racing people will argue vociferously that time isn't the only way, or even the best way, to measure the capability of horses. I would agree if we were splitting hairs over a few fifths of a second. But there is ample historical evidence to show that the times of 1 1/8-mile races such as the Florida Derby are a good gauge of horses' quality.

The majority of horses who have run in 1:49 or better at Gulfstream have gone on to finish first or second in the Kentucky Derby. Those in the 1:50 range on a fast track have been mediocre horses such as Plugged Nickle, Prince Thou Art and Upper Case.

Proud Truth had run five races this winter before his Florida Derby victory; he was well-seasoned and well- conditioned, so it can't be argued that he is likely to improve significantly on that effort.

Horses never win the classics if they can't run faster than Proud Truth did. He may be the most overrated 3-year-old since Seattle Slew.