Buyer's Remorse?

Historically, back when the EPs were being rolled out, the sequence went something like this: Pets isn't ready (that was the next one), it keeps getting sent back for further work and delays, so let's release the one after that early even though it's half-baked and full of bugs. That would be Generations. From a programming perspective, it's the worst EP of the lot as so many of its features are broken or require mods to reel things in for those so inclined. Can't say I would play without it now, but many of us were miffed over what it could have been but never was as an EP even back then.

It has what remains one of the greatest trailers ever associated with it, though. I still get choked up every time I see this one. :)

https://www.youtube.com/watch?v=4hajq1nwsAM