Though we'd tried hard to enjoy Koh Samui, Thailand's "unspoiled island paradise," the rabid dog in our bedroom was the last straw.

We'd planned a week of sun and surf on Phuket, but our travel agent wooed us to the smaller island. "Koh Samui is cheaper and less crowded than Phuket," he'd enthused. "No drunken Marines or Club Med crowd. And by rail you'll be able to see and smell and feel the real Thailand." (We had been scheduled to fly to Phuket.) Since the agent had demonstrated no previous signs of sociopathic behavior, and since neither Barbara nor I are above a little masochistic adventure tourism, Koh Samui it was.

The first small problem arose when we discovered that the train from Bangkok to Koh Samui traveled only at night. Smelling and feeling the "real Thailand" was a possibility, but seeing it was out. Still, the cost was reasonable, and the food and people-watching were good. Not until bedtime did the train's essential design flaw become evident.

Thailand is hot. Even at night. Ceiling fans kept us relatively comfortable. But sleeping was another matter: The overhead lights were left on for security purposes. So we could draw the privacy curtains and sweat in the dark, or leave them open and stay cool in the glare.

On disembarking the following dawn, we were merely tired. But an hour into the 2 1/2-hour ferry ride to Koh Samui, resigned exhaustion had set in. At first we had mistaken the bungalow hawkers for stewards and stewardesses, or Jehovah's Witnesses -- all clean-cut happiness and light at 6 a.m. As the ferry pulled away from the dock, the hard sell came out, along with homey photo albums of the bungalow operations. There was no escape.

We succumbed to one from Big Buddha Beach, on the north side of the island, and on arrival, we met the whole family: Mom the cook, Dad the imperious overseer, all the kids. As we sipped a refreshing watermelon slush, Pon, the eldest son, glanced around conspiratorially. "We have saved a room for you, my brother," he said. Brother? My antennae quivered tiredly. "Very nice, next to the beach," he continued, smiling.

And it was that. A bare 40 feet from the water slap. We moved in, not thinking to ask about the shallow concrete trough below the window nearest the bed.

The answer came at 7 a.m. when a work crew began mixing cement in the trough with hoes and shovels, and piling rocks near the front door. Straggling in to breakfast, we were assured they would be finished by day's end. They weren't. Start later tomorrow, we were assured. Sure enough, work didn't begin the next day until 7:15.

We packed up and headed to another bungalow near the beach. Cheaper prices.

Congratulating ourselves, we settled in to go native.

It was shortly thereafter that we came to understand that visitors to Thailand fall roughly into two categories: those who love Bangkok and those who don't. Bangkok-lovers, who tend to regard carbon monoxide as a major food group, view life in rural Thailand with a certain justified trepidation. Bangkok-haters are only too happy to drop their credit cards and hug a coconut palm. There is no middle ground.

Don't get me wrong. There are people born to sit on deserted beaches and work on the carcinogenic potential of their suntans. Not us. A person can drink only so much fruit slush. We ate, slept, swam, sat, read, played Scrabble and sweated. An awful tropical ennui set in. For comic relief we played with village puppies or took the public jitney into town to watch the drunken tourists.

One dusk, while watching the commuter rush of enormous bats, we could hear dogs clamoring far down the beach. Later, one dog arrived on our porch whining piteously to come in. I shooed it away.

The next afternoon, I was showering when I heard a dog barking very near. I opened the door to see Barbara standing on the bed, snapping a towel, trying to scare something from under the bed. The something was the same dog that had tried to get in the night before. What Barbara couldn't see was its crazed look. It was wild-eyed, lunging at the towel with abandon. I suggested that Barbara leave, and then I began the long, careful walk to where my shorts hung by the bureau, the dog growling and biting at thin air a few feet away. I have never felt quite as naked.

Like most beach bungalows, ours was built on short stilts, with the foundation accessible. Once outside, I decided to try to gain control of the situation. I took a rock and whacked the floor boards beneath the dog, attempting to startle it. Mission accomplished. Howling, the beast came scrambling out and down the porch stairs, making a stumbling, foam-slavering, wild-eyed turn toward where I stood. At that moment I realized my full athletic potential. If the Olympics ever institute a porch-leaping competition, the gold is mine. On the sand, the dog fell over and convulsed rigidly.

It took about two hours to die. There was nothing to do. Everyone we asked replied, "It's not mine." Hom, the maintenance man, told me mad dogs are a regular occurrence. "Bats," he said, pointing skyward solemnly.

Later, when I told the owner about the dead, rabid dog at our doorstep, he replied, "Not mine." Wrung out and tired, I said something unkind. A while later, the dog was gone. Next morning, I followed the drag marks to the water's edge. So much for a swim.

We left Koh Samui the following day. Pon, from our original bungalow, offered us a ride to the ferry when he went to market. At the dock, I thanked him warmly. "You're welcome, my brother," he smiled, shaking my hand, not letting go, quoting a price twice what we would have paid on the public jitney.

I handed over the bills without argument. We were getting off cheap. Charles F. King is a writer and photographer in Hayward, Calif.