Honestly, it's mostly just prejudice. But, I don't see much in it anyway. The both have ice powers. That's all I've seen people ship it for. Well, there's also the strange theory that their personalities "balance each other out". No offense, but

:P

Okay, offense.

Maybe they might be together for a little, but I see them more as just good friends, or even siblings. Not to agree with jackunzel shippers, but they kinda do look like twins.

"They both have ice powers!"

Me: Yeah, and so do a lot of other characters. Frozone, for example, and Periwinkle.

"They look cute together!"

Me: Looking "cute" together is just anyone's opinion. Some people think Jack and Merida look cute together, or Jack and Rapunzel.

I am sure I didn't check out all the points of jelsa shippers, so tell me what I missed. And remember, I'm not trying to be rude, I'm just putting my thoughts into words. Well. most of them. ;)