Why don't i get on with Cancer/Scorpios ..especially Cancer ?

You're basing your observation on only the Cancers that you've met. I am a Cancer and I'm definately not manipulative and talk behind my friends back. I can be sensitive sometimes but to an extent, I don't let it control over my life. Please do not assume that a person with a certain sign has to behave a specific way. Not everyone is the same. I like Leos. They are very strong and intelligent :)