LOS ANGELES—Lost. Sons of Anarchy. Grey’s Anatomy. 30 Rock. The Office. Justified. Glee. Parks and Recreation. They are some of the best, most celebrated, and longest-running shows of recent years. But they also have something else in common: Even their most ardent fans would agree that each of these shows had their strongest, most memorable seasons in the second or third year of their respective runs.

And while most of the actors and producers dream that the new shows they are promoting to reporters at the Television Critics Association’s summer press tour will be on the air for many years to come, the truth is that more often then not, those shows will peak creatively sooner rather than later.

“Everyone’s favorite seasons of shows are seasons two and three, because you’ve had a year to get to know them, and then you’re still in the honeymoon period where you go, ‘This is great!’” Mike Schur, the creator and executive producer of the Fox comedy Brooklyn Nine-Nine, explains to Quartz. “And then after season three, everyone starts to go, ‘Eh, that show’s not as interesting as it was anymore.’ And it’s like, ‘Well you’ve been watching it for three years.’”

It’s hard to argue with Schur’s logic, especially since he worked on both The Office and Parks and Recreation, which also peaked within that season two/season three timeframe. “The bell curve is very common, I would say,” he said. “And what that really means is, it takes a year to get to know people, and then you have this great period of time where the stories are still new, and the world is still new, and the character’s relationships still have to be fleshed out and [there are] surprising reveals and stuff.”