I admittedly have a bit of a bias as before WCI i actually was never interested in One Piece. It wasn't until I saw that art style and became so interested I started reading it, but I have to say up until WCI the foreshadowing done for Big Mom is hands down the best in the entire series.

Thriller Bark- My moms a hero

We meet a gag character named Lola who is obsessed with getting married to any and everybody. By this point we've heard of the other 3 Yonkos but not anything on BM. Lola briefly mentions her mom and how great of a pirate she is and how she'll help the SH's. She gives them her virvre card and this is basically all we hear from her Pre timeskip.

Fishman Island- We stay talking shit

We get Big mom's silhouette as this huge raging cannibal, eating screaming objects what we now know was probably candy. Luffy then apologizes for eating the candy and she doesn't accept it; so he says ima just kick your ass then. she says oh alright, just keep that energy when you see me. He then accidentally gifts her a fucking nuke.

Dressrosa- We not scared of you

So after getting his ass beat by Doflamingo, Sanji sees Big Mom's ship that's 10x their size and thinks "i can take em." splits up the crew (which leads to the 2 best arcs in the new world imo. since Oda actually has time to focus on each character since there's not a ton.)

Zou- We may not have thought this through.

At this point, the SH's have fucked with her ship, ate her food, said they where going to beat her ass yet they bluffing. So Big Mom gives them a nice ultimatum. You can either come to me, or I can go to you and baby you don't want that second option. Sanji still remembering the ass beating from Doflamingo knows what he has to do.

WCI- We fucked up bois, we'll get em next time.

We finally meet Big Mom and she's not nearly as bad as we thought. Cannibal? No it's candy. her kids? she loves her kids except Lola, she fucking hates Lola. Oh wait She is cannibal, Lola REFUSED a marriage, The bomb actually makes sense with the plot?!

WCI was a whole new level of payoff, I know people don't like it because it drags towards the end. but there's just something so epic about Pudding saying "oh you're not helping me by making this cake, you're helping yourself, because she WILL NOT stop chasing you until she gets it."

we don't talk about BM after WCI tho, that's a different post.....