I have been running retrospective activities for a long time. I really like retrospective activities.
Interesting enough, I have not married with one activity.
I try new activities. I brag to my friends about the latest one. Many times I repeat old ones. But I do not settle with only one.
I look around. And I find people that also like many retrospective activities. I also find people that did settle with one activity (well / less well seems to be the most married type). They seem happy with the the same routine.
For the ones who like varying retrospective activities, check out the Agile Retro Activities catalog.