Why is Katrina miffed with Deepika?

Where Katrina Kaif is Ranbir Kapoor's current love, Deepika Padukone was in a serious relationship with the Kapoor clad years back. It was a bad breakup but Deepika is still fond of the 'Rockstar'. Recently at an award function when Deepika was asked what would her New Year resolution be if she would be Katrina, Dippi said,"If I was Katrina, I would marry Ranbir Kapoor." And this comment has not gone well with the 'Bang Bang' actress.