Good news, everybody! The best drama currently on television is going off the air!

FX announced Wednesday that “The Americans,” its resonant Soviet spy drama set in 1980s suburban Washington, has signed a deal for two additional and final seasons. If you love the show like I do, this is — like so many things on “The Americans” — sad but perfect, because it will have the chance to end well.

This strange phenomenon — cheering for the end of one of your favorite dramas — is a curious byproduct of the peak-TV era. Traditionally, networks wrung everything they could out of hits, and TV history is full of greats (say, “All in the Family”) that are greater if you don’t think much about their last few seasons. Ending a veteran series was once more a matter of crafting a bang-up finale episode than plotting a multiseason story arc.

But the more ambitious and serial TV became, the more jarring it was for a series to abruptly end, or worse, continue past its creative peak by fiat. More and more series were naturally driven toward an endpoint, like “Lost,” for which ABC took the unusual step of setting a three-season glide path to its finale. Whether you loved that ending or hated it, it was preferable to spinning out the story, “Gilligan”-style, until the Harlem Globetrotters washed ashore on The Island.

“The Americans” is one of those rare series that actually has gotten better every season. But we shouldn’t kid ourselves that it, or any show, would do that indefinitely.