Your first Aspiration choice matters in that your first Bonus Trait will not change after switching to a new Aspiration. Completing an Aspiration earns your Sim a related Reward Trait, and allows them to select another Aspiration from any category. Unlike TS3's Lifetime Wishes, you may change your Aspiration at any time by pressing 'G' and going to the menu. The Sims 4's Aspirations are life goals that Sims may select, allowing them to complete a checklist of objectives to earn Satisfaction that may be spent toward Rewards. The Sims 4 Aspirations List Reward Traits, Satisfaction Totals, and Milestone Summaries