Polycarp said/asked:
The answer to the implied question is: “Your money or your life.”
Imagine a character on a sitcom being asked that question by a mugger. Maybe tense, but not very funny, right?
Now imagine Jack Benny getting asked that question by a mugger. The pause, followed by the eventual line (“I said, your money or your li…” “I’M THINKING IT OVER!”) was one of the biggest laugh lines in radio history.
But, as Benny later said, that line took ten years to write. By the time that episode was aired, Benny had been on the radio long enough to develop a character that every listener knew all of the details of- arrogant, nosy, and incredibly stingy (as George Burns said, “Jack Benny managed to wipe Scots off the face of the earth. Every joke about the cheap Scotsman turned into a joke about Jack Benny.”), and so the dilemna of “your money or your life” carries the immediate comic weight that it wouldn’t for Groucho Marx or Jerry Seinfeld.
Or, more importantly, for an undefined character.
Therefore, when a show first comes on the air, it tends to write its characters in caricatures and stereotypes. So-and-so is stupid. Such-and-such is black, and therefore rails against constant oppression by ‘whitey’. So-and-so is Jewish, and is therefore more urbane and worldly than the other hicks he’s around. Etc. That way, the writers can get into those ‘absurd situation’ jokes or ‘study in contrast’ dramas without having spent years laying a groundwork. Given the dog-eat-dog nature of modern network programming, you don’t have the chance to lay groundwork. If you don’t hook people with your jokes or your drama PDQ, you run a strong chance of getting yanked.
As shows continue on, though, and have a steady fan base and regularly decent ratings, many usually begin to expand their definitions of their characters in order to better develop them, and lead people to better ‘contrast’ positions. Watch Night Court and notice how Judge Stone starts off as just a wacky goof, and develops into a wacky goof with abandonment issues and a strong conscience. Watch All In The Family and notice how much more human and less stereotypical Archie Bunker becomes. This is also why spin-offs are so popular; you can start a series with serious groundwork laid into a character.
It’s a general rule and not a specific: Law & Order has only rarely stopped to try and define the characters on the show, but still goes on strong after 10 years; I seriously doubt Three’s Company ever really cared much about making anything real about its characters. But the general point is, most writers feel they need to start with characters that are immediately identifiable, and then once they’ve got a decent share of the market and don’t fear the immediate axe, they then start to work on showing the true individualities of that character.