Forms of expression

You know it makes me wonder what's the use of feelings?
Are feelings really there for everybody else than the person itself?
I mean how does it matter if I feel happy or sad if nobody else knows when I am happy or sad.
How does it change anything for I might think something to myself and then later change to something else? It was left to myself...so it didnt affect anything in this world. Expressions are for everybody else...like this blog.
I might want to type in what all I think but what's the point?
Like I asked somebody the other day...blogs arent for myself they are for somebody else because they are a form of expression
Now feelings are expressive in their own way and even if i feel happy right now how does it really matter?
Should it make you sad that even though your mood might change but it doesnt affect anybody or you really dont know what to do with it?
Should you not feel anything that your life is not being shared or would you want it to be shared?
You might want to express your feelings but you dont want it to blow all over the place the next morning...
so its a case of wanting and not wanting at the same time.
In all of this I really dont know why it should affect me or anybody else for that matter.
Maybe I am so used to telling things that it does.
Ah well...music.