A fact, as observed by the OED, is "a particular truth known by direct observation or authentic testimony, as opposed to what is merely inferred, or to a conjecture or fiction; a datum of experience, as distinguished from the conclusions that may be based upon it." If its true meaning is to be respected, fact should not be used to refer to a wish, a hope, a guess, a hypothesis, a theory, an inference, or a judgement.

Poignancy, for example, is not factual:

The fact that this kind of serious material ends up playing puckishly funny as well as poignant is a tribute both to Coppola and to her do-or-die decision to cast Murray in the lead role. *
(Perhaps this observation belongs in a separate article, but even if the assertion is to be taken as fact, it is not the fact itself but rather the reviewer's articulation of it that is a tribute.)

Here is a provocative statement that erroneously attributes facthood to each of two assertions:

The fact that I would [engage in an intimate relationship with] Ann Coulter does nothing to negate the fact that she's a self-hating, conservative, crypto-fascist. *
The first is merely an affirmation of a desire; only if it were realized would the act itself become a fact. (Note that while a hypothesis is not a fact, there is no reason that a fact cannot be hypothesized.) The second postulates self-hate as a basis for political conservatism: a compelling theory, perhaps, but hardly factual.

Note, however, that facts are distinguished from other truths not by the degree of certainty with which they are known, but rather by the manner in which they have come to be known. Logical conclusions may be as reliable as the facts from which they are derived. As any Alabama school child will tell you, "Evolution is a theory, not a fact." * The statement itself is accurate enough, but the implication that the truth of a theory is necessarily subject to doubt is misleading. This particular theory carries the weight of an overwhelming body of facts and is as well-founded as any of them.

Even when an assertion does satisfy the definition of fact, there is generally no need for it to be so identified, as it often is by some overused idiom such as in point of fact or as a matter of fact. In most instances, due to the fact that or in spite of the fact that can be effectively replaced by because or although. George Thompson, a high school English teacher of the 1960's, promised a failing grade to any student who used the locution the fact that in a written assignment, regardless of context. Bill Walsh would have found himself in summer school:

As a copy editor, I enjoy the fact that I don't have to be thinking up story ideas for the next day, week, month .... Different jobs have different advantages. I like the fact that I don't have to pretend Nicole Kidman is important. *
This is a convenient but clumsy method for generating a substantive clause, compelled by the fact that English, unlike other Germanic languages, does not allow a clause beginning with that to be preceded by a preposition. A better result can usually be achieved be replacing the verb with a gerund. What Mr. Walsh really enjoys is not having to think or to pretend; the factual nature of this circumstance is uninteresting.

On the other hand, Mr. Thompson's prohibition should have allowed some exceptions. Whoever drilled this and similarly rigid rules of usage into his particular head was undoubtedly performing a service to all in his belletristic path, but those of us with a capacity for independent reason should be free to recognize the occasional situation in which it is appropriate to emphasize the factual nature of an assertion: *

Parents become resigned to the fact that their child has a disability.
Quantum theory had to be reconciled with the fact that the electrons in Thompson's cathode ray tube experiments followed trajectories governed by Newton's second law.
As Otto Jespersen once asked,
But is the fact that a grammatical construction can occasionally be turned to bad purposes an argument against its being used where there are no evil consequences to be feared?
At the same time, one must beware of insidious uses of this phrase intended to disguise conjectures as facts:
Doesn't the fact that the universe is so well designed mean that it must have had a Designer? *
(Watch this space for a future entry on BEGGING THE QUESTION.)