What makes a great rivalry in anime?

[Claraviolet]

So what do you all think?
Do you have any such criteria? I believe honest and competitive(friendly) rivalry is always cool xD

 

[Blackangel]

may be rivalry between really good detectives lol
but i don't see any such cool rivalry here at all which is a bad thing for anime.

 

[Sincerem]

Already the protagonist and antagonist are rivals in the animé movie series. They tend to fight for a common goal and xD, Lol.