My first contact with One Piece was watching a random dubbed episode.
It was Baratie Arc. I THINK it was the fight against Gin? I just saw that dude with a suit, fighting with kicks.
"Damn that character is kinda cool".
A year later a friend tells me to watch One Piece from start. I remembered Sanji and thought "oh, the anime with that cool kicking character. Ok, gonna give it a shot".
Sanji is the reason I actually gave One Piece a chance. Reaching Baratie and seeing how cool he was there was one of the best moments I had with OP in general.
Oda's gotta do some REEEEEEEEEEEEEEEEEEEEEEEEEEEAL nasty shit aside from overused japanese pervert gags, for me to dislike the character.
Besides, I've played and DM'ed RPG for years. I played and met my fair share of flawed characters and badass characters. To me, flawed characters are way more relatable.
Sanji's Vinsmoke arc also reminded me of Zuko, which made me look at Zeff as some Uncle Iroh. This made me love these characters even more.