Dicisions... Decisions...

Have you ever decided something but then you 've changed your mind?
Why does it sometimes happen ? Is it because you've not been sure of ur decision? Or because your decisions are usually shaky?!
I think lots of facts are involved here such as.....

But I don't like it when i cannot make a firm decision.

My Idea:

Decisins are made because of many obvious reasons, some of the reasons are hidden or forgotten, when sucj reasons become clear we have to change our mind and it's good.