After moving to a new city, I got pink eye, then got it again, then again, and again. Eventually my doctor noticed that I got it the same time of year, every year, and concluded it was an allergic reaction. No wonder the antibiotics never seemed to do anything. Now that we know the cause, I can prevent it. I'm glad. I was starting to get sick of the annual tradition of people informing me that I must've gotten poop in my eye.