We have countless threads about suggestions where to travel. In a different twist, I think one that discusses the opposite might be helpful, or entertaining to some.
My list includes the places I would not CARE to visit again and some I would if I had no other options. Here we go:
Places I’d rather NOT visit again:
Even without the recent news, Athens
Tijuana
Rosarito
Places I rather would skip
Sao Paulo
Portland
New Orleans
New York
Costa Rica
Panama
and a few more
I’ll add:
San Francisco - expensive, crowded, and dirty, no matter when we visit. Have to give it some credit for its public transportation.
Pretty much a day in the city is plenty to see all of the touristy things. Venture outside and stay outside of the city to save a few bucks.
I’ll skip Tihuana. I will not visit New York City again, too expensive, too many shops. Big Island is another not visit again. Same with Oahu.
I am very glad I visited Costa Rica but would not do so again. Simply way overpriced I think.
I was going to say Carcassonne, and then I remembered my last business trip to McAllen, Texas. It’s all relative.
You guys have some of my favorite places in the world on your lists!
The Atlanta airport.
Lol, Lergnom. I think Chicago O’Hare beats it.
(My cats are saying any vet office is not worth visiting. )
LaGuardia 
I have mixed feelings if I would go to St. Lucia again. I was in awe of the beauty there and enjoyed our stay so much, but I struggled so much with the culture shock and was so exhausted by the time we arrived that I was terribly homesick the first night of our trip. I am used to being in America, where my husband and I are treated as a unit and not split up on purpose by beggars and people DEMANDING tips for insane things. People trying to separate me from my husband so they could get away with hounding me made me immensely uncomfortable. I am used to having waitresses who don’t act like someone is going to beat them if they drop a spoon. I like road signs and speed limits. I spent most of the trip sitting on the beach with our cabana butler, hearing about her life and feeling horrified and powerless to do anything about it. I loved the beach but so much of the trip made me uncomfortable. I guess I am just not a very worldly person, and there are many places I will probably not ever see.
My husbands answer would be Australia. He is so glad he went once, he loved it and it was the trip of a lifetime, but he doesn’t think he could do that flight again. I don’t think I would have even attempted it the first time.
Some places are easier to say they aren’t worth the visit when you’ve already gotten to do it once.
Las Vegas. Do not get the attraction at all.
And I agree with San Francisco - I enjoyed two days there, but really I’ve been a few times and there’s nothing I need to see.
Disneyland - went once in college. Our kids have been deprived since we never wanted to go again.
Aruba. I hated it. Ugly island.
I love traveling to big cites, but I absolutely hated Dallas. Would never go back.
Any amusement park.
The Adirondacks. Damp and buggy in the summer. Bitter cold in the winter.
I agree with @mathmom . I would just as soon never ever go to any Disney park in my lifetime. Living in So Cal, the best thing about your kids growing up is not having to go to Disneyland ever again.
Oahu, mostly because it’s a warmer version of LA at this point. I do however love the Big Island, and want to visit the other islands.
Orlando. As a native Californian I LOVE Disneyland, so I have no need to go back to Disneyworld.
Tijuana, Juarez, not very nice places now that I’m out of college. Would love to go back to Rosarito/Puerto Nuevo/Ensenada though.
Disney – thank goodness my kids had no interest – DH and I did NOT want to go
Las Vegas, New Orleans – wretched excess is not our thing
Tijuana – eight year olds begging for coins really shook up my kids, who were about the same age, though the lessons about compassion and privilege are still burned in their consciences.
Korea.
I’m curious if the Portland referenced in the OP was Oregon or Maine. I’ve only been to the one in Maine and would definitely visit there again.
Vegas. Been multiple times. Hated it every time.
Bahamas. I didn’t like a single one of our stops there.
Bratislava (Slovakia), Kalamata (Greece)
Amusement Parks: Six Flags, Disney (went once with each kid to CA and FL and that was more than enough), and Seaworld (FL)
US cities: Indianapolis, Milwaukee, and Las Vegas (Didn’t choose to go, but went for conventions to all multiple times and wouldn’t go again.)
This thread is kind of risky, if posters happen to be living in the cities mentioned as craptastic. If all one sees in a city are the airports and Ramada convention rooms, much is left unseen.
Yes, I enjoy some of the cities listed and have visited several happily multiple times, SF, Portland OR, and of course I live on Oahu. Yes, I am not a fan of Las Vegas but have a friend who moved there and is very happy.
I enjoy Disneyland and have been there at least a dozen times.
I like the Big Island but have trouble breathing for a week after visiting when I spend time there, due to the volcano, so haven’t been back in the past few years.