Greetings!

Guilty. I have one. There is a Greatest Hits on there... Let's see...

Replace Gordon Lightfoot: Gord's Gold with Vince Guaraldi: A Charlie Brown Christmas.

I would make an exception for live / concert albums. While I agree that it may have songs from various other albums, as long as the performance is solid, it is really capturing a point in time of the band's career. Especially if the entire recording is captured live from one session, or if the band edits and releases it themselves as a mix from a single tour.

In many cases, there are works available live that are not available at all in studio form (Phish: Gamehendge & Broadside Electric: 10th Anniversary Concert) or are (in my personal opinion) a different or superior work to the studio edit (Renaissance: Live From Carnegie Hall disk 2 - Scheherazade live with a 20+ minute Ashes Are Burning & Marillion: Thieving Magpie - Misplaced Childhood played through live).