IMO, it's the core of why he sacrifices himself.
Sanji tends to think that "if I am the one dying, then it's a fair price to pay". It's less about true sacrifice and more about "better me than someone else".
And that's not how it should go at all.
It's a very thin line and he needs to understand that difference.
When Zeff saves Sanji, he doesn't just "die". He endures on that island despite giving sanji all the food.
When Sora takes the drugs, she isn't trying to suicide, she is just trying to prevent her children from becoming monsters. She endures as long as she could.
When Rouge holds Ace in her womb, she doesn't do it because she thinks she is a fair price. She does it out of love.
Love.
Sanji fails to see the difference between a sacrifice done out of love and the sacrifice he usually does because he thinks he's more expendable than others.
But Sanji sacrifices himself for those he loves lol
It's not different. He cares about his friends and would die for them.
And the things he remembered realy show, that this whole sacrificing tendency is a bad reason.
It's not like he was sacrificing himself just for the sake of it...
- The only one where you could use it as an argument is the Zeff situation. I honestly don't remember there whole context there, so you can correct me here.
Sanji was willing to die for Zeff's dream (yes? No?), but let's be honest, Sanji besides from his Mother never experienced love like this. Zeff ate his own leg so Sanji could survive - thats a huge contrast to what his real father did. Ofc in his mind, that was a debt he could never repay. But Zeff obviously cares more about Sanji than his dream. That was probably stil completely new for Sanji, to know how a good Parent actualy thinks and treats their children.
Sanji stil did it out of love and gratitude.
Luffy had a very similiar situation with Shanks, but Luffy grew up completely different, so he came to a different conclusion.
The other example are completely different.
- Sanji saving Nami and Ussope from Enel is the only thing he could do there, getting them out of danger and letting them escape. Nothing else he could have done different. This has nothing to do with him seeing himself as less worth - his friends were in danger so he jumped in.
-The next one was i think Thriller Bark? The sentence is different, maybe because of the bad translations or Oda changed it, whatever. Zoro did the exact same thing there, yet he got CoC and didn't block it lol
- Then we have Sanji kicking them out of Bege, because they were literaly at Gun Point in Bege's Castle and Sanji had no choice but to go with them, because of the threat of BM killing someone close to him. He had no choice here.
- Then the WCI situation, Sanji saw no way out and if not for Oda's retarded writing, there literaly was no way out. I remember people saying ''He JuSt NeEdS tO beLiEvE iN lUfFy'', but nobody could ever give a realistic answer to how to solve the problems Sanji was facing.
Which some came out as lies, but we didn't know that until later, while the other thing, like BM being able to kill any close person to them just never played a role against the SH's after they left WCI, because there is literaly no way to protect everybody around the world. So Oda acted like it never existed...
And the only thing Sanji could rely on and hope, was that they (Judge and BM) would keep their word and just to go along with everything so his friends stay safe and don't get involved. I also remember people saying, but how can he believe the enemy, because that was the only thing he saw a chance of solving all the problems. There was no other way.
He didn't wanted to get anybody involved, because of all the reasons and the enemies they were up against, it was a death trap. Asking your friends to basicaly do the impossible and suicide is not something a normal person would do. But thanks to plot armor they made it out...