What's the worst expansion pack and game pack and why?

They kind of fell short with Island living. It's great we have mermaids. However, I would have liked to have abilities for mermaids like singing that have effects on other sims. A flirty song, a sad song, a happy song, an energizing song etc. that would give other non-mermaid sims those buffs. I would have liked to have had an underwater world for the mermaids. I would have liked the beaches added to all worlds.

Seasons broke the game for me where there were too many bugs. When a new pack comes out I play vanilla and slowly add back in my mods. However, instead of it taking a few days, it took a few months.

I like spa day but it was lacking. It was more like a game pack than an expansion pack.

University I guess is the ones I like best followed by City Living.