Anna Kendrick and Bill Hader make a “great couple”. The 36-year-old actress and Bill, 43, have been dating each other quietly for more than a year, and according to an insider, they already have great “chemistry” when they’re together. The source told People: “You can see the chemistry when they’re together. They have a really fun rapport, very sarcastic and funny but all coming from a place of love. “You’d think she’d be the one kind of running the show, but she’s pretty quiet around him.” The celebrity duo already “really love each other”, according to the insider. The source shared: “They’r…