Why do people decide to write autobiographies?

Question

what do you think is the reason?

Answer 1

Because they are famous and other people want to know what they did to get to where they are.  Or because they have an interesting story they'd like to share and they think is important for people to know, or they have a cause that they've worked hard on and would like to raise awareness for it.  Personally I prefer the latter.

Answer 2

Mostly people who write autobiographies are bored celebrities who want to make money off their life story. Except maybe Joni Erickson Tada, who became famous for sharing her life story after being paralyzed in a diving accident and turned to Christ as her Savior.

Answer 3

Many people write autobiographies because they think their life is very different and interesting... and many people forget that nearly everyone thinks at least some portion of their life is different and interesting.

The few really good autobiographies are written by people who already write or tell stories in some capacity, and who are talked into writing their life stories by others who know them well. [Or by their creative writing students, as happened to Frank McCourt (Teacher Man being his best, I think).]