Great question. This is one of the lessons I teach in my workshop (linked below in my signature), and I’ll give you some quick answers that doesn’t require you to spend a week on in-depth lessons on this subject.
Stylistic choices are as you probably guessed, not always going to be effective. Effectiveness can mean different things depending on context and needs. For example, being endearing might be a goal when you are creating a style that appeals to a specific target audience. Grittiness might be for a totally different audience. There are also others like cuteness, quirkiness, humor, somber seriousness, idealized beauty, etc.
The various stylistic parameters an artist can use to create a unique stylization is actually limited to just a few, and once you know what those exact parameters are, you will be able to deconstruct every style you see much more effectively, as well as be able to think about your own stylistic approaches much more critically and with an exacting sense of purpose for specific goals.
There are lots of ineffective stylizations out there, and often it’s because the artist did not match the appropriate stylistic parameters to the target goal, thus coming up with styles that does not actually enhance or match the tone of the intellectual property or appeal to the target audience. In my workshop we explore lots of examples of failed and successful stylizations and examine why they failed or succeeded, and what the circumstances were (how the style relates to the needs of the intellectual property and target audience).
Yes, it is very easy to create bad/ineffective stylizations, and there are so many examples all over the web that you might run into every day. To get deep into the subject of the anatomy of stylization and the range of parameters will require a lot of time and space, which is why it’s part of my 8-week workshop. We spend an entire week on this subject, as well as deconstructing aesthetic sensibility and parameters of idealization used in stylization of male and female characters, as well cultural differences in those preferences.