Modifications are not a joke. When used incorrectly, you can cause serious damage to your game.
Okay, back on topic. You know what I would really like to see? Teens having their own highschool cliques. It would be neat to have cheerleaders, glee kids, jocks, nerds, plastics, etc. So many premade townies, could be used within certain cliques based on their personalities/traits. Maybe the high-school, could provide after school activities, that could appeal to our teenage Sims based on their traits. (Virtuoso Teens, join the marching band, or choir, Artistic Teens can join the art club, charismatic teens, could join debate, athletic teens could join a sports team, Genius or computer geeks, can appeal to the Science club etc.) Teens can get a part time job, why not have them join after school activities? Even have their own cliques?
I want my toddlers to have their own set of toddler like mean interactions too.