These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Americans Hate Tingle: Not *hate* exactly but still a difference in appeal - North America: pretty successful, but just another group. Rest of the World: popularity rivaled that of the Beatles.
Germans Love David Hasselhoff: On the flipside, they were especially successful in Japan and Australia. Just take a look at the massive, screaming crowds in ABBA: The Movie. Ironically, "Take A Chance On Me", their second most popular song in America (after "Dancing Queen"), didn't even crack the top ten in Australia.
Then again, at the time ABBA was most popular worldwide, Fleetwood Mac had the prime position in the North American market, so to speak, on melodic, harmonic pop. It was pretty hard for anyone to compete against the Mac at the time of Rumours. For that matter, the parallel between the two groups in terms of couples that broke up but kept on working together is pretty eerie...
They were very popular in Latin America, especially in Mexico in the 80s.
Another factor could have been Americans weren't that used to hearing foreign sounding singers at the time. Even most British pop/rock artists sing with an American accent.
Agnetha and Frida did acknowledge that they had a rivalry - but one that belonged on the stage. They said it added to the dynamic and energy of their performances and made for better shows. Offstage, however, they were quite good friends.
Vindicated by History: The more pretentious type of rock critic (and rock fan) liked to deride Abba during their heyday as being little better than bubblegum pop; as Björn pointed out in a 2002 Australian interview, "for the main part of the group's lifespan, the critics despised us". These days, a lot of people appreciate the group for their musical and vocal craftsmanship, and for their innovation in the field of music video (see Trope Codifier).
Specifically people like to mention how dark The Visitors is, 'dark' being a codeword for cool amongst music critics.
It has also been made clear that rather than a faceless pop band, ABBA's playing pop and disco music because they were the most popular amongst the various styles they did. Bjorn and Benny could easily have been a hard rock band as evidenced by such songs as Watch Out, experimented in funk with Man In The Middle, not to mention the progressive rock stylings of Hole In Your Soul.
Furthermore, Bjorn And Benny's self-deprecating sense of humor regarding most of their songs means that you know their cheesiest moments are just as cheesy to them too.
"Honey Honey" is really about sex, so much that in the version heard in Mamma Mia!, when the lines "you do your... thing" and "you're a dog-gone beast" are sung, the singer is clearly enjoying herself.
"Voulez-Vous" is about a consensual one-night stand.
"The Winner Takes It All" is about divorce.
"Does Your Mother Know" is about trying to invoke the Jailbait Wait, in the sense that a legal minor is all but throwing themselves at the singer. Very much not kid-friendly.
"Hey Hey Helen" is about a woman whose has recently left her husband for an unspecified reason. It is implied that he was abusive to her. Her kids miss their father, but she never wants to see him again. The song essentially is trying to help them all cheer up. This is quite a dark meaning for such an upbeat tune and it is not surprising it was just an album track.
"Gimme! Gimme! Gimme!" is about being horny.
"Under Attack" is about someone being chased by a stalker of a lover.
"The Visitors" has the singer in a police state about to be hauled off by the authorities. The line "they've come to take me/come to break me" implies that the singer knows she's about to be tortured.