Probability. A Rant

 Today's rant is about dice.

I play with a lot of different gamers, some fun, some not so much. Everybody approaches their gaming differently, but one thing is sure, we all game using some sort of random number generator. In most games, that's dice. In Malifaux, it's cards. We understand, intellectually, that if I'm rolling a 20-sided die and I need at least a 15 to succeed, that's a little better than a 1 in 4 chance. Not great odds, right?

And yet, on the table, people are astonished when they aren't rolling crits every single round.

"Man that sucks! I only made, like, a third of my ward saves! These dice frickin' hate me." Well, Einstein, your ward save is a 5+ on 6-sided dice. A third is exactly what you should expect. The probability of rolling a 5 or 6 on a d6 is exactly 1/3. So yeah, the dice are doing what they're supposed to be doing.

Here's one I got once:

"The spell landed? But I have a 65% magic resistance!" Yep, it landed. Saving throw, please. "Even with my magic resistance?" Yes, even with your magic resistance. 65% odds do favor you, but it should still not be such a major surprise when it doesn't go your way. 2/3 of the time you'll make it, the rest of the time you won't. It really irritates me when a player regards 65% as being about as reliable as 100%, and then questions whether I'm DMming fairly.

Same player:

"What? He saved against my spell?" Yep. "  Well, you know how the saving throw works, right?" Yep. "Are you sure?" Yep.

He'd cast a spell at an enemy and the enemy, who needed a 5 or better on a d20 to save, made the roll. The spell had no effect. "Sheesh, I can't believe he made that." Another lesson in probability, boys and girls... If you need a 5 or better on a d20 to make a save, that's 80% likely to succeed. Good odds, definitely in the target's favor, and far from a huge shock when it's made. Certainly not enough to start a rules-lawyering session in mid-game over it.

Same player (AGAIN):

"He hit me? But my Armor Class is -1!" (In AD&D, low AC is good. a -1 AC in 2nd Edition is equivalent to a 21 AC in 5th Edition.) In the case I'm thinking of, the enemy monster was a 9 HD beast with a THAC0 of 12. That means on a d20 it needed a 13 to hit an AC -1. Adding its bonus for Strength and the magical weapon, it only needed 9. It was likely to hit. I always fail to understand why people are surprised to be hit when their attacker has better-than-average odds of making that hit.

We assemble our characters, our armies, our whatever for gaming and we have to think about the odds when the time comes for the dice to hit the table. You've got to be realistic about this. When the odds don't favor you (or even when they do) and the dice don't roll your way, complaining about it and registering shock actually drains the fun away from others, because it sounds too much like whining. We're playing games that use random number generators. That means a certain amount of gameplay is simply outside of your control. This is meant to account for all the little factors that can't be covered by the rules. Sometimes even when the odds are in your favor bad things can still happen.

I remember a game once in Warhammer where my Bretonnian knights charged an enemy Dwarf unit and scored 4 hits. Each hit only needed a 2+ to cause damage. I rolled 4 '1's.  Another time I had a unit of Black Templars that were 3" from an enemy unit.  I declared a charge.  I rolled snake eyes.  The charge failed.

Frustrating?  Yeah, but what can you do? Sometimes you'll roll all crits. Sometimes they'll all fail no matter how good your odds are. Now mind you, this example is one in which I had a reasonable expectation of getting 3 - 4 successes. This is why I find it so silly for people to be surprised when the dice provide exactly the results the math expects.