Now a lot of people will immediately dismiss this as nothing more than a weirdness in lighting but I feel Gimple and them did the final scene with Rick's right eye darker for a reason.(Notice his right eye is darker than everywhere around it, mirroring the Governor's eye patch)
I don't think it means he is becoming the Governor like so many people have accused me of trying to say, I just think they are foreshadowing that he is about to show no mercy to the people of Terminus like the Governor would. Or that what they'll do to the people of Terminus will be pretty dark. Or pretty much that Farmer Rick is gone for good. I just wanna hear other peoples thoughts/opinions on this as it has been eating at me. All opinions are welcome.