Some years ago it was Franky and/or Brook.
But now it's clearly Chopper. Useless garbage on all points. He is useless in combat and everything, he cries and is scared all the time and it's very annoying (it's supposed to be a gag ?) and cringe, his role as a doctor is useless now that Law is around, his post-ts design is not as good as the one before ts ect ect .
Ussop is annoying to never evolve mentally. Even Nami now has more courage (to say in front of Ulti, despite the threat, that Luffy will be king of the pirates).
Sanji has been getting lower and lower in my esteem since pre-ts, but I still appreciate him.
Oh and I forgot Jinbei
Annoying fish not compatible with the crew.
Chopper is the worst then there is Jinbei/Ussop.