I think I read a thread like this before, and perhaps even wrote it. If so, I apologize.
I rapidly change my perspective, depending on what the weather is, or if I talk to someone I know, or if I am alone. This happens very regularly. It is predictable that it will happen, but not when and how it will happen. I think I cycle between positive, neutral, and negative outlooks, and these outlooks have to be shaped by a forecast of how the future will be, at least for the next few hours or something. If something the next day is going to be bad, then I can cast a cloud over it sometimes, but most often not.
Within the positive, neutral, and negative outlooks, there are all kinds of variations. I find this to be very not helpful because it makes it hard to know how good your decisions are.
For example, I might be thinking in a very neutral way about what I am working on at the time, and then the telephone will ring and I become intensely annoyed. I won't necessarily realize that I am annoyed, or not sure what to do, or whatever mood has been stimulated by the telephone and who is on it; one time I picked it up to talk to someone and was hardly able to get the words out, as though I was very unsure of myself, even though I was not conscious of this in my mind. The disconnect is sometimes very clear.
Does this make sense to anyone else, or is it more of a 'me' thing?