#2. The Album With One or Two Disproportionately Good Songs
Entire careers, and in fact genres, have been sustained by albums where no one song ever really stands out over the others (see: literally everything except mainstream pop/rock), so it's not a lack of hits that makes for a bad album. It is, ironically, when you stick a real classic in there among regular tracks that throws everything off. Everything is relative, and when every song on an album is roughly equal, then you've got yourself a decent album. When every song is decent except for Track 1, the culture-straddling megahit, then you've got yourself a severe perception issue. Everyone was cool with the pizza you ordered, but when you open the box, there's for some reason one slice in there from the gourmet place uptown, and now it's one-tenth of a good pizza instead of a nice dinner. It doesn't actually suck, but perception-wise it's completely diminished. You don't know what you've not got 'til it's here.
An extreme enough instance can even poison a band's entire catalog, leaving them wrongly perceived as a "one-hit wonder" instead of a reliable and consistent act (the difference between Billy Bragg and Chumbawamba is "Tubthumping"). Of course, if you can manage to relentlessly crank out an endless string of terrible albums with two good songs on each of them, those songs will add up and net you a lucrative career, but not everyone's in love with money to that extent.
#1. The Dreaded 3 Stars Out of 5
Much like the worst direction you can go in is no direction, so is inoffensiveness worse than taking a stand, and thus the boring album is in a way worse than even a terrible album. An album that is full-on awful will always get minimal scores, but an album that is accomplished but boring is going to attract the dreaded three-star review -- so often the calling card of the most inessential music of all (if your album is best described as "pleasant" then you're in serious trouble). A one-star album can't be boring, because even if the music is godawful, it's WHY it's awful that is itself entertaining -- a one-star review is inherently entertainment, which is why you'll always read one when you're skimming the reviews column. But who the hell wants to read the three-star reviews, particularly as they're all identical ("IT'S NOT TERRIBLE, BUT IT'S LACKING. IT FALLS SHORT, BUT IS A STEP IN THE RIGHT DIRECTION"). And boring as fuck.
The opposite of enjoyment is not disgust; it's tedium, because in a life so cruelly short, there's nothing worse than being forgettable. The most disgusting pizza I've ever had was the one that accidentally had dish soap in it (SECRET FAMILY RECIPE), yet of all the ones I've eaten, it alone has survived the years as an amusing anecdote. It's the middling three-star stuff you won't remember. The albums from artists you respect that you've had forever but played once (REM are like your parents -- you know they're good, but you never listen to them). A reworking of ratings systems might help, but if we've gone this far without rating entertainment based on how entertaining it is, then why start now? The accepted method of rating albums isn't terrible, of course, it's just lacking. It falls short, but it's a step in the right direction. I'd give it ... 3 stars out of 5, let's say.