Friends:

Seeing own past Lives & all their Mistakes!

Once when the Venerable Anuruddha was dwelling at Savatthi in
Jeta's Grove, in Anāthapindika's Park, a number of Bhikkhus went
to the Venerable Anuruddha & exchanged polite greetings with him.
Then they sat down & asked the Ven. Anuruddha: Venerable Sir: 
What has the Venerable Anuruddha developed & cultivated so that
he has attained to his famous greatness of direct knowledge?
It is, friends, because I have developed and cultivated these four
Foundations of Awareness that I have won great direct knowledge.
What four? Here, friends, I dwell constantly contemplating upon:
The Body as a formed group, neither as me, lasting nor pleasure!
The Feelings as passing sensations, neither as mine, nor pleasure!
The Mind as temporary mentalities, neither as I, nor as core soul!
All Phenomena as mental states neither as substance nor any real!
while eager, clearly comprehending, & fully aware, thereby removing
all desire & frustration rooted in this world! It is, friends, because
I have developed & cultivated these Four Foundations of Awareness
that I have become empowered with all these suprahuman forces:
I remember many of my prior lives, one rebirth, two lives, three lives,
four lives, five lives, ten past lives, twenty lives, thirty lives, 40 lives,
50 lives, a 100 past lives, one thousand prior lives, several hundred
thousand lives, many aeons (universal cycles) of world-contraction
and expansion (big bangs): There such was my name, species, family,
such my appearance, such was my food, such my experience of any
pleasure and pain, such was the story of my life; passing away from
there, I was reborn elsewhere. There such was my name, variety,
family, such my appearance, such was my food, such my experience
of pleasure & pain, such was my life length; passing away from there,
I was reborn here. Thus I recollect manifold various past lives and
abodes in all their particular modes & all their spectacular details...

Source (edited extract):
The Grouped Sayings of the Buddha. Samyutta Nikāya. [V:305]
section 52: Anuruddha. Thread 22: The Past Lives.

Comments: There one sees all the times one has been a killer, a thief,
a crook, a hero, an ordinary being and all the possible evil things one
has done not one time, but billions of billions of times in this looong
Samsara - The dreadful round of rebirths. A truly humongous sight! 

On folly longing after a now unreal past, that has passed never ever to return:
http://What-Buddha-Said.net/drops/II/No_Nostalgia.htm
http://What-Buddha-Said.net/drops/II/At_All_Times.htm
http://What-Buddha-Said.net/drops/IV/Anti-EGO-Tool.htm
http://What-Buddha-Said.net/drops/IV/Hidden_Horror.htm
http://What-Buddha-Said.net/drops/IV/Seing_Past_Lives.htm

Seeing own past Lives and all their Mistakes!