Familiar is hands down the best card with a potion in its cost, so if people aren't buying it it's just because your group doesn't realize how powerful cursing attacks are. (Or you play a lot of 4+ player.)
I am actually starting to put my hands up and say vineyards has a spot in the discussion.
As a fun or not fun card? Or another part of the discussion?
I think as a "most powerful potion cost card"?
Oh. Perhaps, but I thought the point was to inform bodybuilder with which expansions he may like. He doesn't even like Chancellor because it's not that useful. I get the feeling cards like Familiar won't impress him.
Thread discussion tends to wander after a while.
Familiar can be swingy, and that can irk some people... but it happens. bodybuilder didn't complain about Swindler or Torturer (and yeah Torturer can be swingy -- who can get the chain going first?) so Familiar might be OK for him. I'm actually not sure what he's not a fan of, aside from specific cards. Some are generally not bought (e.g. Chancellor), some are frustrating and often weak (Saboteur). He also seemed not to want to play with extra components (like VP tokens). I can't figure out a general thing he dislikes.
Best advice is just to try everything. If there are cards that are disliked, remove them. No big deal. Honestly, everything is balanced and everything can shine in at least a few scenarios, or not be worth buying in a few scenarios. Some just are usually almost always worthwhile or worthless. But nothing is 100% always bought or always ignored, I think. But if you dislike a card, there is no great reason why you can't leave it out.
you missed some step .. I am using add-ons and I like them, I learned to use chancellor, and the other cards. the only one that I take off is saboteur, because with him the games are completely different.
my question was if cornucopia and seaside have cards that make the game frustrating (as saboteur).
I do not like alchemy, and will not take it.
The problem is that we don't know what you will find frustating, and what you have told so far does not really give us a good position for guessing. Anyway, Seaside and what others may find frustating:
Sea Hag: Sea Hag is Curser (like Witch) that doesn't help your deck (like Saboteur) and is avaible the first turn (as it only costs $4) and curses very fast. This leads to quite messy decks, because all these Curses and also Sea Hag will bring down your deck value. It's probably the most extreme Curser in the game.
Pirate Ship: Pirate Ship destroys opponents Treasure. In 2p, it's a usually bad card that can help your opponent more than it hurts if they know what they are doing, but often leads to group-think where everybody in the group buys Pirate Ships, which leads to horrible decks where now one can afford anything as all the Treasure is destroyed. And the worst is, as everybody bought Pirate Ships, a Pirate Ship player wins, leading to the impression the Pirate Ship is the best card of the world, so everyone will buy Pirate Ships in the future.
Ambassador: Usually not considered a good card by new players, it actually is one. Games with Ambassador (in 2p) often start with both players passing Estates and Coppers to each other for several turns. After this, often one player has a clean deck and the other one has a messed deck, such that the game is essentially decided, but might take some more time because it essentially just started, as all this ambassadoring took a long time but didn't do much.
Smugglers: Another weak card that can be group-thinked into a strong card.
Ghost Ship: Being under constant attack of Ghost Ships might also be not that much fun for some people.
Note that these are only the cards that for some reason some people find annoying, it doesn't imply that they are. I myself actually wouldn't ban any card from Seaside, even the strong ones like Ambassador often allows alternative strategies countering them.