I have this too, but I think this is relatively normal, as mixed feelings and moods are described in many novels - they seem to be part of human experience. I think both are real, plus many people tend to stick to something positive of the day and regurgitate it in their mind to get along better with the sad things.

About the opinion thing - I have found out that the more complex a topic is and the more pros and cons pile up, the more difficult it becomes to come to a conclusion. For these kinds of things, being unsure about what to think about something means either you don't want to form an opinion for lack of information, or that you have so many pros and cons that it's difficult to pick a side.

Sokrates or Platon when he was old said: "I only know that I know nothing."

and I think this is what he meant. Indeed, I often get the impression that people who form a fast opinion and never re-evaluate it are... well boring, previsible and often shallow, plus often not very bright. I think this has more to do with intelligence (real intelligence, not the kind of "good at learning for school" thing) than with being bipolar, though your mood might play into it too.

It is also a cultural thing. In western civilization, we are used to a thesis-antithesis-synthesis approach, this comes from the ancient Greeks. It means you pile up the pros and cons and evaluate them and then you have to draw a conclusion. The Jewish way, e. g. in the Talmud, is different: thesis-antithesis and thats it. They pile up pros and cons and leave it to the reader how he will decide, or if he will leave the question unanswered altogether for himself and NOT pick a side - it is a more open approach.

You DO NOT have to pick a side.

Moreover, the western culture has a tradition of dualisms, such as

culture - nature
white - black
male - female
mind - body
etc.

where things are regarded as belonging either on one side or the other, one being superior over the other, and these things have the corresponding side of some of the other dualistic attributes belonging to them. This means, if something is inferior in one regard, it tends to get the other inferior attributes stuck to it, and the same goes for superior attributes. You can see this e. g. in medieval and up to today convictions that women can use their minds less than men, are more sensual than men, belong more to nature whereas the culture comes from men etc. These dualisms are very ingrained in western culture and there are plenty of them, and being bipolar just doesn't fit in as the mood changes from one side to the other and one is not "crazy" (inferior) all the time.

Other people who don't fit neatly into an either-or-category experience often experience a struggle on the way to find their identity and who they really are as there is no predefined category for them in our society. However, once they find their identity they tend to be more open-minded about other things which usually get squeezed into 2 boxes.

Maybe this plays into it as well in your case? As I don't know if it's really "the only right way to be" that one is equally extrovert or introvert no matter who you deal with and what your mood is and how tired you are. I think being bipolar might play into this identity trouble thing, though.

Now, being extrovert on the outside and introvert on the inside, this can also be a cultural thing. There are different regions in Germany where people tend to be different (mind you, a country just as small as Tennessee or something like that!). The Colonians are known to be like that, many of them, it's just the mentality of the city. Very easy to come into contact with, but they won't open their heart to you easily or tell you much private stuff unless you're really good friends, my parents lived there for a couple of years. You might blend in there very well.

Sometimes it's difficult to sort out what is due to being bipolar and what is due to being a human being, and I don't know how it is in your case but sometimes I tend to see everything through the "it's all because of your disease" glasses. Which are not empowering. Moreover, once you look over to other cultures you might find out that not all what is considered "normal" or "abnormal" in one culture is so in other cultures too. Thinking or being outside the box is often sanctioned in a culture, and it is difficult to rid oneself of the prejudices.

I hope this and the other postings are of some help for you and wish you a good sorting out of things.