Why use boolean literals in logical tests?

Ok, I've seen this enough to assume there is some benefit or reason for this style.

When a condition must be tested in code it is not that uncommon for someone to have
code like this:

Code:

---

if ( var == true)
    //operation

---

My question is this. Why not just use code like this:

Code:

---

if (var)
    //operation

---

The clarity seems good for negating a condition better than using the "not" operator "!".

I think that:

Code:

---

if (var == false)

---

is more readable than:

Code:

---

if (!var)

---

But of course it would be really confusing to see:

Code:

---

if ( (var == false) == true )

---

Which isn't too different IMO from

Code:

---

if ( var == true)

---

I mean "true" is the only condition that an "if" statement will trigger off of so to me it doesn't add too much value to clarify that.

I believe that some classes taught like "C" encourage explicit testing because the C language treats *anything* but zero as true which might not be logically what you are trying to do and there is no "bool" object which can only be true or false.

In C if a "TRUE" constant is defined as 1 and "FALSE" as 0 then testing for equality against the constant "TRUE" is more deterministic in many cases than using boolean logic. In C# and Java I haven't seen this *as much*.

Where library designers have provided good method names such as "File.exists" it looks particularly akward to include the "==true" test.

Does anyone know of any differences (in C#) between the two styles?

David