On Not Being Happy But Not Exactly Unhappy Either and is it a Problem?

So. I get anxious around those whom I would uncharitably describe as the "insistently-happy." A polarizing undercurrent sets the tone for even our most casual chance encounters; it's as though I'm understood to either be enthusiastically pleased to see them and to be in the world generally, or to find life itself (and them, by extension) hateful to me,without the possibility of a middle-ground. The only possible modification on these two modes in the other's perception would be an intensification, which would permit ecstasy or sheer rage.  The experience is to normal interpersonal interactions what fundamentalism is to religion.
At some point the sentence will be released into the air between us that conceivably can be either a greeting or a very serious question. With this sort of person, it is typically communicated more or less as the former, but with an unsatisfactory response, it will transmogrify into the latter. In example:

"I'm okay."
"Only okay?"
"Yeah. I mean, yeah, I'm doing pretty well."
"Why aren't you better?"
"I dunno?"
"Do you want to talk about it?"
"You know, I think I really am okay."
"Are you sure?"
"Uh, yeah."
"Okay. But if you ever want to talk about it, you can talk to me."
"Thanks?"

I am pleased for my friends for whom emphatic well-being colors day-to-day life. From my current perspective, I just don't see how it can be a reasonable expectation for everyone else. It becomes especially problematic when it's given moral weight, as if to suggest that it is wrong to experience negative emotions, even if they (appropriately) correspond to negative situations. And somehow, even more neutral emotions - feelings of "only okay" - are similarly, implicitly, condemned. These are big exclusions from the spectrum of emotional appropriateness for people living real lives in the world: be happy, or you're not "being" correctly.
But being "okay" is just that - being okay, right? It's what a "C" was before grade-inflation. Satisfactory, but with no reason to call it great. It helps to make sense of real sadness and real joy, for the difference from "okay" that both of those are. Of course, emotions are complex and this is a very simplistic way of looking at them, but I think there still is something to be said for an average state of affective affairs, when it is appropriate. In the least, I don't think "only okay" should signify that something is seriously wrong.

So, "insistent happiness:" I think it is primarily some kind of maturity issue, because I do have a number of friends who are doing really well in life generally, and who don't feel a need to force that well-being down the throats of those around them. I spent a couple hours with one of these friends tonight; she gave me the wonderful gift of listening to me talk out some things that have been bringing me down, without wantonly doling out prescriptives intended to immediately resolve The Perceived Problems. That's a real kindness - a small, good thing, in Raymond Carver's words. So thanks Emily. You're really pretty great.