Didn't expect to see this as such a quick response to the prompt, but this would be my answer too. My brother got to see them back in the day, but by the time I came to appreciate them myself, I'd missed the chance to see them, so I'd snap up tickets in a heartbeat if they ever had a reunion.

Amon Amarth is some excellent Viking metal.

Alestorm is entertaining pirate metal.

Valient Thorr has a shtick where they claim to be sent from Venus (although musically, I grew to like them less the more I listened to them).

Okilly Dokilly was a Ned Flanders themed metal band (although again, I'm not particularly recommending them, as I really didn't care for the one song of theirs I heard).

Austrian Death Machine was a side project of the frontman of As I Lay Dying (the one who served time in prison and has since been released) based entirely on Arnold Schwarzenegger movie quotes

I'm sure there are a ton of others I'm not thinking of off the top of my head, but these are the first ones that jump to mind.

Agree on Drunk and Hot Girls and Drips (one of the few songs I disliked enough to wholly delete it from my library instead of just skipping it)

Disagree on Fitter Happier and White Light, but to each their own.

As for a few of my own opinions--I wouldn't even consider most of these to be that bad, just a little abrasive and dragging while listening to the album:

Coat Check Dream Song - Bright Eyes (not even that bad, but a skippable weak spot on an album full of 9s and 10s)

The Black Rainbow - Coheed & Cambria (I thought the album was a good return to form overall, but the closer draaaaags)

Probably a controversial opinion, but Time - David Bowie (I love Bowie, but both the music and lyrics of this song are too self-important and come across as "I'm 14 and this is deep" to me)

Not a whole song in itself, but the end of The Shrine/An Argument - Fleet Foxes (the whole album is so serene and/or transcendent, so the ugly horns are so jarring and feel unnecessary)

Teeth - Lady Gaga (Such an unexciting and repetitive closer to an album with no fat otherwise)

Mango Pickle Down River - M.I.A. (I appreciate the intent, but the beat isn't great, and the recording is weak)

The Kids From Yesterday - My Chemical Romance (It would be fine in itself, but the drum sound is so distractingly bad)

One of my favorite music video concepts was "Sic Transit Gloria...Glory Fades" by Brand New. It blew my teenage mind haha.

This is a very niche answer, but might be the single song I've had the biggest turnaround on. "Sabbath Prayer" from the Fiddler on the Roof soundtrack.

It's set up to be so skippable. It's nestled between two more upbeat songs, "If I Were A Rich Man" and "To Life." It's just a prayer, so it doesn't advance the plot. It's very slow to start, with a long, quiet intro for a stage piece (~30 seconds). Even when the first lines kick in, it's very morose, and the two voices are mostly repeating a single note.

I don't know when I sat down to listen to the whole thing, but it's so worth it. If it comes across as slow, that's of course because it's supposed to be a serious, contemplative moment of prayer, and appropriately, it builds into something rapturous. As more voices are added, the harmonies get more complex, and they start to have different vocal lines weaving amongst each other, all culminating in one of the most epic sung chords I can think of. It's simply beautiful, and I never skip it now.

To give you an actual answer to your question, I think "Return of the Mack" is among my favorites. "I'm Gonna Be (500 Miles)" is also high on my list in terms of song quality, though I know The Proclaimers hace more than one hit in other regions.

The main reason I wanted to reply wasn't actually to give my answer, but to let you know that there's a whole YouTube series about one-hit wonders called One Hit Wonderland by the creator Todd in the Shadows. I'm not affiliated with the channel or anything; I've just found his breakdown of the pre-hit and post-hit careers, plus commentary on the song itself, to be an interesting lens through which to learn more about pop music history.

While I don't have any stories of this particular experience, I thought I'd at least share one amusing experience with a music store employee. About three years ago, my wife and I stopped at a dying FYE in a dying mall. I was wearing a shirt from the then-final shows of the band Thursday. I picked up a couple of CDs, and as I was checking out, the employee took a look at my shirt and exclaimed "Shut UP with the best shirt in here!" and gave me a high five. Come to think of it, he did end up recommending another band, but I didn't check them out at the time and have since forgotten. Shame on me.