OMD's Pop-culture corner: Exits that spelled a show's doom

Every week, as I sit down to watch that week's installment of Downton Abbey, a mixed sense of dread and disappointment creeps into my mind.

The show isn't the same as it was in its first few seasons. Some of the change is because the creator has elected to take the show down a few dark passageways that were detrimental to the show. The fourth season storyline revolving around Anna was a terrible misstep, as was the imprisonment of Bates.

The bigger problem, however, is that two of the show's most endearing characters--and one could argue that Matthew and Sybil were the lifeblood of the show--were played by actors who wanted to leave the show after its third season. In the seasons that have followed the show has seemed to be adrift, rudderless, and it is largely on account of the departures of the two characters of the upstairs segment of the cast who had the biggest hearts.

As Downton Abbey has flailed since the exits of Jessica Brown Findlay and Dan Stevens, it has made me think of other shows that were ruined by the departures of key characters. NewsRadio was irreversibly ruined when Phil Hartman was murdered. Northern Exposure was a shell of its former self when Rob Morrow requested that he be written off the show. Though the show was already a bit of a mess by the time he left, The Office got immeasurably worse for the duration of its final two seasons (until the last episode or two) after Steve Carell left.

Sure, Cheers recovered nicely after the departure of Shelley Long, but for every Cheers it seems there is an abundance of shows whose fortunes tanked when one of the key ingredients to the program's success exited stage left to never be seen again.

What character's departure do you feel most harmed a show you loved? Was it Judy on Family Matters? Morgan for the two or three seasons that she vanished for on Boy Meets World?