I am a very complicated person to figure out. I have figured myself out, but others have a hard time.
So that is why most people cannot figure out why my mood is as is on a certain day.

The factors that effect my mood are as follows

Time of day
Music I am listening to (If any at all)
The weather conditions
People associating with me
Colours I am wearing (More as a visual aid to my mood for people)

Time of day effects my mood in different ways
If it is the morning I am generally a cranky bastard
If it is night I am a happy fellow
If it is noon, (depending on that days events) I can be yay or blah.

Music is pretty self explainitory

Weather conditions are a big part of my mood. If it is a gloomy day, raining, thunder/lightening, hail, any storms I am in a good mood.
If the day is sunny, clear, hot, or anything good, I tend to be pissy.

People is pretty self explainitory

And colours are a big one too.
For me to be in a good mood, I wear birhgt colours as most people do. But that is very rare. The only other colour I am seen in is purple (aside from black) but that is usually an indicator to GO AWAY!
Black is my main colour of choice. If I am wearing it most people don't know what to expect. I could be happy or sad. Either one.

So in general I am very complicated.
Yay for complications! . . . To peoples mood!