Is it love?

What do you think is love? And according to your definition of love, is it possible for some one to love a person for more than 3 years up to today and hate that person from tomorrow?

According to my definition of love it is not possible. If any one says it is possible then they will depend on what that person did today?.
Now you came to the correct point. This is where my actual question starts.

What do you need to hate some one you loved upto now?