Progression systems in games are far too often designed as Skinner boxes: psychological traps that feed us carefully measured rewards to create habit-forming activity loops. Skinner boxes are not rewarding in themselves, but progression systems can be, and they should be used to create a better game experience. Building in choices that allow the player to select their own build (and optimize it) lets the player think ahead and makes progression a part of the game experience in itself. It also helps them become familiar with the systems in the game at their own pace as they level up. These systems can even actively make the game better by encouraging players to try and then improve on the most engaging types of play, giving rewards for skill or strategy, for example. Finally, they can actually enhance the story, giving the players faction alignment that responds to their actions in the game and locks or unlocks hidden parts of the story as they progress.