A bad sitcom is forced. In a bad sitcom the characters that you’ve come to know will do things that you don’t believe they would do. Not because their actions are unbelievable (it is not well known that every action is to a certain extent impossible when weighed against the endless possibilities it was not) but because their actions do not fit their profile. A profile if we had to define it is, to a certain extent, what a personality of a given type would do in any situation. We can say that we are not types that we are individuals but it may be true that all of our particular attributes or actions can conform to particular types, in the broadest sense and acknowledging that types do not in fact delineate or determine action; in any case what is a sitcom but a study of types? The free-spirit, the obsessive-compulsive, the slacker, the “straight” man or woman. Etc. And when these types perform actions—responding to situations—in ways we don’t expect, not because we expected a particular action from them and not because we are disappointed by the redefining of their type—for every character must undergo change of some sort because experience is in itself a form of change—but because the action strikes us more as a means of advancing the plot rather than a response to a situation. And an action that is performed for the means of advancing a structure outside the character, outside the character’s world—unless the character perhaps has a knowledge of the plot—can’t help but strike us as cold or flat because it is a betrayal of the character and of the process the character belongs to and of the experience of watching types react (if this is done in bad faith—because of laziness—and not knowingly, although if done poorly knowing a thing does not make it work).
I have always had trouble with unmotivated action because I did not believe that anyone could act according to something that was outside their selves. Conversely (and maybe paradoxically) I also believe that any one can do any thing in the right situation and with the proper impetus, and that the right situation and/or impetus can be essentially any thing. The characters I have witnessed up to this point have been at least convincing even the odd times action has seemed incongruous it has conformed (as I later find) to a type. This kind of incongruous action is extremely disconcerting because it suggests not only that our possibilities are more limited than we suspect but also that type can dictate action.