Absolute control over Probability. There is an infinitesimally small chance of ANYTHING happening at any given time, if you could manipulate that chance to ensure it happens you are basically omnipotent.
It's all about the taboo, but physical attractiveness is important too. In games where all female characters have g-cups regardless of age, taboo doesn't matter. The models are just unattractive.
Do you prefer to play a game as designed first, and add mods on the 2nd playthrough? Or do you implement mods right away for a more personalized experience?