Surprise is an essential element on makeover TV: On "Knock First," it's the parents who see only the finished project. On "Trading Spaces," it's all the participants.

Viewers get to see everything, of course. Still, New Englanders who've participated in "Trading Spaces" have a few surprises to share anyway. Maybe it's not that startling to learn that the renovating is chaotic and often worse, but it's at least a little surprising to hear of quarter-sized holes left in the walls, cheap paint that's sometimes sloshed over wallpaper, and plaster pocked by wallpaper scorers or made brittle by premature painting.

The real shock, though, comes when you hear whether they would go through such horrors again:

"Yeah, I had a great time," said Stephen Ashwell of Feeding Hills, whose episode was filmed in September 2001.

"Definitely. It was a lot of fun. The people on the crew all have great senses of humor," said Jerry Howland of Roslindale, whose episode was filmed about the same time.

OK, but what about Steven Frost, of Cumberland, Maine? Surely he's unhappy, after seeing those quarter-sized holes they left in the corner where the camera was mounted. "Plus, when you're painting, you can't paint around there because of the cameras. And you've electrical cords for all the cameras, all over the floor, so you can hardly move. There's always four to six people in the room."

So you didn't like it, right?

"It ended up one of the most pleasant experiences I've ever had. It surprised me to death," he said. "It just revised what I was thinking about young people today. I thought they were all goof- offs, but they [the crew] were great."

Amateur psychologists might attribute Frost's extreme enthusiasm to extreme initial reluctance to participate. His sister-in-law, Ellen Quinn, had hatched the plan with Frost's wife, Joyce Frost.

Joyce has a different explanation: "He fell in love with Genevieve" Gorder, the designer they worked with on the show. It's true: His shameless flirting raised a nation's eyebrows.

Still, a residue of his reluctance helps explain the barn-board laminate that still covers a wall in the Quinn home, much to the disgust of Ellen and her husband, Daryl. Joyce Frost, a real estate agent, was aghast when Gorder proposed it. "I tell my clients if they have it [the laminate] up to take it down immediately if they want to sell the house. And here I am putting it up!" Part of the reason she lost the argument, she said, was Steven supported the move. "But he was just trying to get back at Ellen for getting him into it," Joyce Frost said.

Jeanne Worrick of North Grafton, whose episode was filmed in September 2001, emphasized several times during a brief interview that being on the show "was a good experience, basically." One of those times she added, "I don't want to sound bitter, because it was fun, and I knew what we were getting into."

Bitter? Why would she be bitter? "They leave your house a total mess," she said. "They don't put anything back."

Maybe it was the closet: "We had sliding doors and they wanted to replace them with bifold doors. They measured wrong, so they tried to build in the framework of the door. For the camera, they nailed up some boards and painted them white so it looked like the bifold doors fit. They didn't even hang the doors. They just leaned them up against the closet."

Or maybe it was the bed: "They took it outside and sawed off the head and foot and put it back in the room. About six months ago, I noticed that it was falling apart, and it did, I'm sure because of what they did. Now we just sleep with a mattress and a box spring on the floor, like college kids."

"But I don't want to sound bitter because I knew what I was getting into," she said.

Kathy Davidov, the Learning Channel's executive producer for the show, said such results are "certainly not the norm. It's not our intention to leave homes or projects in that condition." Davidov, who's been working on the show for seven months, observed that that episode was shot in the first season. "I don't know the specifics, and it's hard to respond to a specific homeowner. But those aren't the standards that I know. We don't jury-rig these things," she said.

"Trading Spaces" is one of cable television's foremost success stories, as well as the cornerstone of a home-design franchise at the network. On the show, couples swap homes for 48 hours, during which they completely redo one room in the other couple's house. They do much of the work themselves, led by a designer and sharing the aid of a carpenter. The designers can spend no more than $1,000.

With a budget like that and designers motivated by the medium to be outrageous, it's a wonder that any of their plans survive the week. Some couples said they didn't change a thing, but the tinkerers are winning out: For example, when Ashwell returned home for the "reveal" (the show's term for when couples return home and see the changes), he saw blue stripes on the wood floor of his living room.

"I was wondering why they'd left painting tape on the floor. When they finally left after some more shooting, I walked in again and said, `They painted my g-d floor!' That got me a little bit, but that's part of the show," he said. He has removed the stripes, as well as a white rug placed near the door that quickly soiled. He said he repainted the room, too, "because they missed a lot of spots, and behind one curtain they patched but didn't paint. It's a two-day show so you know they don't have time to work miracles."

Theresa Franceschelli of Roslindale, who swapped households with Howland, also has made a few changes, including removing a rug. "I don't know what it was made of, almost like a straw. It was very rough and very uncomfortable to sit on or walk on. And every time I tried to move it, like when I vacuumed, the floor was covered with this material that the rug was made of."

She also no longer uses the bedding cover in her daughter's room: "It was white. It was very nice, but I put it in the washing machine, and it shrunk. Now I can't use it anymore. So there were little things," she said.

Fortunately for the couples involved, their friendships have endured beyond the designs. Many of the seven couples interviewed said the experience had strengthened their relationships. "It was positive," said Jim Fenton of Portland, Maine, whose episode was filmed in June 2002. "You really let your complete guard down when you're spending a night in your neighbor's house."

The only negative hint came from Joyce Frost, who teasingly suggested that her sister Ellen "felt a little disappointed that we got a better kitchen than she did, since she's the one who put us on the show. But no, we didn't hate each other or anything."