This entry on TV Tropes is about TV shows that get cancelled because the network did not treat them well.
The reasons are diverse, and aren’t necessarily objective or intentional.
Often a show is screwed over because it did not get enough promotion. Obviously, a show can’t get high ratings, if not enough people know that it even exists, though of course there are times where a show if aggressively promoted and still fails. Another reason is scheduling; a show might get low ratings if it airs at an inconvenient time, especially against rival networks’ most popular shows. Sometimes, business politics leads to cancellation. For example, on ABC, the show Lois and Clark had been renewed for a fourth and fifth season; however, afteer ABC was purchased by the Walt Disney Company, they wanted to air a revival of The Wonderful World of Disney in the same time slot of Sundays at 7 PM (to be fair, the ratings had significantly dropped). Lois and Clark was cancelled at the end of season 4, leaving the show on an unresolved cliffhanger (which is a common thing that happens to prematurely cancelled shows).
Other shows are screwed over, ironically, due to their attempts to make them better. NBC had Up All Night, created by former Saturday Night Live (SNL) writer, Emily Spivey, and starring Will Arnett, Christina Applegate, and Maya Rudolph. The show originally focused on Chris (Arnett) and Reagan (Applegate), dealing with the trials and tribulations of raising their newborn daughter, Amy, with Chris being a stay-at-home dad, while Reagan goes back to work for her boss and best friend Ava (Rudolph), at a PR firm. When Rudolph appeared in the film Bridesmaids which was hugely successful, NBC decided that she needed a bigger part, and the role of Ava was re-written to be a talk show host, with Reagan being her producer. However, the show would be re-tooled again. At the start of season 2, Ava’s talk show was cancelled; however, the ratings were poor, and not much, if any better than than they were at the end of season 1. NBC halted production after 11 episodes so that they could re-tool the show yet again. It was to change from being a single-camera comedy to a multi-camera comedy; as if that weren’t a drastic enough change, there were other proposals for changing the show. To quote TV Tropes’ page on the show, “Some truly nutty ideas were thrown around, such as baby Amy being able to see a portal connecting the single-cam world to the multi-cam world. In the end, they settled for the completely sane concept of having the entire show turn out to be a Show Within a Show, and from that point on follow the lives of the fictional actors playing Reagan, Chris, and Ava.note Seriously, we’re not making this up. .” However, the third re-tool would never happen. Spivey departed the show, not wanting to deal with all that nonsense anymore. Applegate soon jumped ship as well, leaving the show without one of its stars. This killed the show, but NBC did not officially cancel it until the end of the season.