The my dictionary comment drives me nuts. When people do this they accidently or purposely trying to redefine a discussion or argument. They are changing the very language used in the discussion. People cannot freely exchange ideas if one person starts changing the meaning of the words used in a discussion according to their feelings about the word.

I don't mean how words change over time...I mean in the very discussion itself...might as well be speaking in a language the other person doesn't know.