(n)an absent part, especially in a book or other piece of writing.
And you are what you are so no one is to blame right ? Except considering your fault in expecting too much from them :)
There is no one to be blamed here... neither yourself for in the first place they themselves set a standard of their own by behaving in a particular manner and then you define them in that manner only.
Words are all that this blog is made of ~ From me to you, And words are all that I crave for ~From you to me!