Randomness has three major functions in game design: 1) it creates exciting moments, 2) it gives the weaker player a chance to win occasionally, 3) it forces players to adapt to changing circumstances. When adding random elements, game designers must look at the delta of randomness, or the difference between what baseline impact that element has without a random effect and the realized impact it has with its random effect. Hearthstone once again provides an easy example: a card with a random effect should have its baseline below the average power curve on the assumption that its realized random effect will boost it over the curve. Surprisingly, cards with the least variability in their random effect tend to be more exciting for both players than cards with a large but unreliable random effect. Large randomness can swing the game in ways that make it seem like the outcome was decided the moment one player lucked into a huge random draw. But small random effects can still give one player a slight advantage without completely shutting down their opponent, giving both a chance to play around the inherent RNG in the cards.