Why is Windows Spider Solitaire so unfair? Probability question.?

Spider is a great game, but unlike freecell, there are losing deals, i.e., there is no solution for some deals. These deals are not random, nor pseudo-random, but by list. These games were saved because the programmer, or a programmer's program, determined that they were interesting, or challenging, etc. You have to recognize these unsolvable positions and know when to give up on a game.