The false belief that newer entries in a series or franchise have somehow degraded in quality over time. Mostly used for series that have been around for a very long time. Named after the long running show, The Simpsons.
Person 1: Man, AVGN is shit nowadays!
Person 2: No, really, it isn't, the humors as funny as ever, and so many great episodes have come out in the modern AVGN era. Hong Kong 97, Seaman, Life of Black Tiger...
Person 1: B-But, everyone else thinks so!
Person 2: No, actually. Look at the most liked comments on any video and you will see that they are all positive. Seems like a case of Simpsons Syndrome, eh?