If you are defining crack as "crazy impossible", it's reasonable to think KyouMami applies. Just look at Rebellion, it shows us that no matter the circumstances that main couples will always come together. Kyouko gives up her life for Sayaka time and time again, Sayaka risks her soul to spend time with Kyouko, and Homura does to the literally ends of the universe to protect Madoka. It's crazy to think any other pairs would happen.