Everyone has some of these, list yours. Weird opinions, whatever.
Exodus - Bonded By Blood: I fucking love Thrash. Reign in Blood and South of Heaven were the first extreme metal albums I ever owned. Discovering Kreator changed my outlook on riffs forever. I count albums by Forbidden/Artillery/Testament/Annihilator/etc. etc. etc. as some of the greatest of all time. I just can't see the appeal of this. Some of the choruses rule, but I just can't get into it. In terms of early thrash, I think the first two Metal Church albums are both better.
Iron Maiden - Powerslave: Don't get me wrong, Maiden is my favorite band of all time. I fucking worship them. I listen to Maiden daily. However, I can count the number of times I have spun Powerslave as a complete album on one hand. Compared to the thousands of times I have listened to every other Bruce era 80s album as a whole. Don't get me wrong, you start with two of the greatest songs ever written, and end with two of the greatest songs ever written. But the middle 4 are some of the worst filler Maiden ever put out. The flow of the record has a huge lull in the middle. They aren't bad songs. But the first two are godlike and the last two are godlike that the middle is really lackluster by comparison. I would still call it a legendary album, but I won't ever listen to the whole thing. The running order isn't as strong as the other 4 studio albums of the classic five.
King Diamond - Abigail: Great album. I would just never listen to it over The Eye, Conspiracy, or Them.
Megadeth - Rust in Peace: Megadeth was the first concert I ever saw. I bought this record really early on. Never enjoyed listening to it. The riffs are immense, the playing is immense, there are a couple great songs, etc. etc. etc. But as a whole, I don't think it's aggressive enough. Give me Peace Sells any day.
Candlemass - Nightfall/Ancient Dreams/Tales of Creation: These are supposed to be fucking legendary. Can't stand 'em. I love Epicus Doomicus, the white ST album, and the two most recent ones. But why would I listen to these when I could listen to Solitude Aeturnus, which is light years better? Rob Lowe wipes the floor with Messiah every day of the week. These are three insanely over rated albums.
Iced Earth - Burnt Offerings/The Dark Saga/Something Wicked: These are supposed to be their best according to most. No thanks. I'll take Night of the Stormrider (best vocals Iced Earth had), Horror Show, and Alive in Athens.
Death - Human/ITP: These aren't pleasant to listen to. At all. Most think they are their best, but I'll take TSOP, Symbolic, and Leprosy.