Sanji knew what he wanted to see in his future. He wanted a beautiful wife with a cat or a bird as a pet, living in their restaurant in the all blue. He would be the most respected chef, with the most elegant lady and they would have no children because as much as he didn't want to voice it - like the thought could make it into reality, he didn't want any kids. Too afraid they'd turn out like his siblings, or even worse - as useless as himself.
So of course, when a devil fruit user sends him flying twenty years into the future, he doesn't believe it when his crew says that none of it was true. The future must be wrong, right? But what truly makes him lose it was that not only did he have three kids but he was apparently married to the most brutish and grumpy man alive. And if being married to Zoro had upset him that much, everyone was dreading the moment when past!Sanji would find out he lost an arm protecting the future he so strongly didn't want.
