It depends of a lot of factors and context while trying to avoid any kind of spoilers. For example, if I'm interested in reading a romance series the first thing to check if it has the "Dense Protagonist" tag and the demography. Shonen, for example. Then let's say it has 20 volumes and you know what to expect with a combination like that. No development until the last volume, and a lot of infuriating situations prolonging the whole thing. Not to mention if you add harem or shit like that. You know exactly what to expect and since it's not my style, I avoid those.
Then you have insta interest-killers like rushed endings comments or tags. Story, characters or art can be good but you just know that it will have an abrupt, weak, or even worse, a no-resolution ending.
