I finished a game yesterday which ends where it begins. I've written before about reflection in game stories. Coming full circle is a great way to encourage it.
People don't reflect automatically when they finish a game. Reflection needs to be encouraged. One method is juxtaposition of the before and after. Ending a game where it began is an easy and effective way to draw attention to things that have changed.
Fable 2 does this with Bowerstone, but in a crudely overt way. It's more engaging when you don't bluntly tell the player things have changed. Show, don't tell.
For example, suppose the main character in your game arrives with friends but leaves alone. You can have the character perform a particular activity with the help or input of those friends, then perform that activity again alone. Setting alone is not always enough to recall memories, but actions usually are.
What are some experiences from games you've played which encouraged reflection?