Memories

Memories are collected by Sims in The Sims 2 and The Sims 3: Generations.

The Sims 2
Memories are stored in a panel in the Sim's information box. Memories can be good or bad (determined by the Sim's aspiration). Bad memories can cause Sims to grieve. All memories, good or bad, can become topics of conversation, and Sims who hear about these memories also get an invisible "marker" of the memory, which means they can gossip to other Sims. Positive memories are shown in green, and negative memories are shown in red.

Bon Voyage adds a sub-box to this called Vacation Mementos.

This feature is not included in The Sims 3, however moodlets act as temporary memories, and Sims will often remember major tragedies like deaths of family or friends and divorce by occasionally crying. Memories are reported to re-appear in The Sims 3: Generations.

The Sims 3
This feature is not included in the base game, however moodlets act as temporary memories. Larger event moodlets will last longer, ex: a death or divorce. Sad moodlets will make sims cry every once in a while until the moodlet goes away. Memories return in The Sims 3: Generations, the Sims will collect them, and it's possible for the player to change a Sim's memories, its description, and a tool to create memories will be available. It will be possible to share memories on social networks such as facebook.