Each of Cell's forms had their own specific personality...almost as if they all had seperate minds. If you'll notice, all three of his major forms had discret, if not major differences in them. Ofcourse, deep down inside they were all one and the same, but Cell's forms seemed to go through the same phase as us humans; adolecence. Let's look at how each of his forms diefferated between themselves.
::Cell: The Music::
::So saith Goku::
"If I were you I'd get off this planet! Trust me, you don't want ANY of this.."