In 1987, two sitcoms with similar premises, one on NBC, the other on ABC, premiered. One limped along for three years and the other became a hit. Yet, as is often the case in TV history, the one that became the hit wasn't necessarily the better of the two shows. And that's being extremely magnanimous.
In NBC's [italic]My Two Dads[/italic], which premiered on September 20 of that year, Paul Reiser and Greg Evigan played two men who have to live together to raise Nicole (Staci Keanan) the daughter of the now-dead woman they both slept with at the behest of a Judge (Florence Stanley). Despite the improbability of the premise and the overall mediocrity of its execution, powerful competition on CBS from the 9th ranked [italic]Murder, She Wrote[/italic] and its erratic scheduling on top of that, it still managed to rank 21st place for the year, even outranking [italic]Day By Day[/italic], the show it alternated the coveted post-[italic]Family Ties[/italic] time slot with but could only muster 43rd place; [italic]Ties[/italic] came in 17th. But [italic]Day By Day[/italic] was from the same producers as [italic]Family Ties[/italic], which gave it the advantage at renewal time; it made the fall schedule while [italic]My Two Dads[/italic] had to wait until mid-season to come back. It did make the 1989-1990 fall schedule while [italic]Day By Day[/italic] ended up being cancelled the same year its more celebrated lead-in bowed out voluntarily. But by mid-season, it kept getting moved around between Wednesday and Monday, and NBC decided it was a lost cause, so they cancelled it.
[italic]Full House[/italic]'s premise wasn't particularly outlandish in and of itself—a widowed dad with three daughters asks their two uncles to come live with him in San Francisco and help him raise them—but the dismally poor quality of its execution belied its eventual ratings success with children, religious fundamentalists, the severely mentally disabled, and people who will someday be legally forbidden to live anywhere near a public school. Its popularity was such that it is even getting a sequel series in defiance of popular demand. I needn't bother to reiterate its monumental artistic shortcomings; there's a review blog that does just that episode-by-episode by someone with a will of iron and the self-esteem of a martyr. I will point out that they wanted Paul Reiser, but since [italic]Two Dads[/italic] got him first, they had to settle for Bob Saget, who at least knew shit when he smelt it but still shut up and cashed the check anyway.
In its first season, [italic]Full House[/italic] ranked three whole ratings points below [italic]Webster[/italic], the show it replaced that ran for another two years in first-run syndication anyway despite still pulling better ratings in its last ABC season than [italic]Full House[/italic]'s first. Coincidentally, Chad Allen had appeared on [italic]Webster[/italic] in a recurring role before NBC cast him in [italic]Our House[/italic], which also aired on Sunday nights and overlapped with [italic]Two Dads[/italic]' first season. In its final season, Chad got cast as Staci Keanan's "bad boy" boyfriend; to that show's writers, being a "bad boy" meant wearing torn jeans and driving a motorcycle and had little to do with actual social rebellion.
Another coincidence is that a year after the dust had settled, Staci Keanan ended up on Miller-Boyett's almost equally awful neo-[italic]Brady Bunch[/italic] wannabe [italic]Step By Step[/italic], the show that rose from the ashes of [italic]Dallas[/italic] and [italic]She's The Sheriff[/italic] and got [italic]Full House[/italic] moved to Tuesdays.