Sanji getting himself captured by Black Mariah despite having:
1. His incredible speed to get away fast enough.
2. His Observation Haki to see who's about to attack him
3. His fucking raid suit that he instead used to SPY ON WOMEN IN AN ONSEN as opposed to going invisible and just using that suit to save a woman he thought he was going to be raped.
It's only stupid for these reasons but also because of Oda's idiotic attempt at showcasing payoff for both Robin & Sanji since they're two members, aside from Nami, who had issues asking for help. That's why Sanji calls for Robin.
Sanji COULD have asked for assistance taking down Queen but no, this stupid shit instead happened.
Other examples include Big Meme's stupid amnesia subplot, Tama's bullshit fruit, and Mink drugs tho the pay-off for that remains to be seen.