The third season was my favourite and I was worried that adding Amy into the cast would jump the shark and ruin the show just as it was really hitting its stride. The writers managed to integrate her pretty seamlessly into the flow of the show and a lot of the storylines with her and Sheldon were done pretty well. My only worry is that the writing for the rest of the show is starting to fall off slightly. The whole situation with Leonard and Priya felt forced and seemed like it was only added into the show to bring Leonard and Penny's lingering feelings to the surface. This could've just as easily been done with Penny's on and off boyfriend Zack who was a much funnier character.