It is true that many atheist are the first to fight the argument that God exists yet as you say they can't prove it
The burden of 'proof' rests with those who claim that "god" exists and yet, no substantive evidence has been presented by those claimaints. Those challenging such empty claims do not have the obligation to 'prove' nonexistence because that's an irrational premise. One cannot disprove the existence of 'pink unicorns' however, it does not logically follow that pink unicorns exist.
and yet they are always asking people with faith to prove with facts. Makes no sense.
It makes sense if logic is used and doesn't if 'faith' is relied upon instead.
I believe God exists.
Such a belief does not not confer existence, it merely indicates an empty opinion, (one the lacks a supporting basis other than baseless 'faith').
I also think that although I might not be able to prove 100% percent to everyone that he does exist, face to face, I could crack any atheist of his believe that God doesn't exist because there is no proof.
To reiterate, 0% 'proof' of such an existence has been offered to date. Disbelief is not a 'belief'; it is being dubious of the unsupported claims of existence made by 'believers'. Given this premise, it is extremely doubtful that you could "crack any atheist" by failing to support an unsupported claim, (whether here or, face-to-face).
The fact of the matter is that there are a lot of things in this world that point to the existence of a greater being.
The vague assertion made constitutes an unsupported opinion since no directly-attributed evidence to substantiate them has been presented. If you have any, feel free to present it.
But since there is ultimate no way to check, these kind of arguments have been raging since the stone age. Good OP.
If there is no evidence to support a claim, such a claim constitutes an empty opinion.