While "Do No Harm" got yanked after TWO episodes, which is nowhere NEAR a fair chance. (grump)
It used to be the case with nearly all TV shows that you could start watching it at any point in any season, and have whatever episodes you watched make sense, without you having seen previous episodes.
A lot of modern TV dramas are different. You have to have watched the very first episode in order for the second episode to make sense, and every episode builds on the previous episodes.
24 stands out to me as the first example of such a TV show that I ever watched. If you didn't watch the very first episode of
24, then the second episode wouldn't make sense. If you didn't watch the second episode, then the third episode wouldn't make sense. And so on. But each episode left you eager to see what was going to happen next, insuring that you were certain to tune in for the next episode.
From a ratings standpoint, this means that such a TV show really needs to attract, in its first episode or two, the audience that the network thinks it will need to make the show worth continuing. If it doesn't pick up enough audience in the first few episodes, then it probably isn't going to, ever.
I suppose it's a trade-off that the networks have to gamble with. An old-style TV show, where each episode stands on its own, can attract new audience at any time, and it can also lose audience at any time. A modern serial drama can only really attract audience at the start, but once hooked, that audience is more likely to keep watching, as each episode leaves them eager to see what happens next.