Do many women have an idealized view of themselves?

I know a lot of women who seem to look at themselves through rose tinted spectacles. Fat women who think they are slim and sexy, older women who have damaged their skin through smoking, sun worshiping and drink who imagine they still look youthful I could go on. On the other hand I have know a few very attractive women with the opposite problem where they greatly underestimate their beauty but it seems that most women are more inclined to delude themselves that they are more beautiful than they are. Why is this the case?