! is a bad operator

In C#, C and C++ the exclamation sign (!) is used for negating a boolean value.

This is considered a bad thing because it is so small and easy to miss.

    if( !IsPostBack ){...

I would like to write

    if( Not( IsPostBack ) ){...

instead.  But I have yet to find a way to overload it such in C#.

Even with the improved readability of "Not" it is easy to think wrong.  It is way too easy to get lost in negations in a just slighty complex boolean expression.

A way to improve readability is to avoid the useage of ! or negations at all:
    if( IsPostBack ){
        // Does nothing.
    }else{
        ...
    }