Professor: "Don't do anything that affects anything. Unless it turns out you were supposed to do it, in which case for the love of God. Don't not do it!"
Fry: "Got it."
 http://www.gotfuturama.com/Multimedia/EpisodeSounds/3ACV19/12.mp3 

During time travel it is possibly best not to disturb anything. But is the prime directive a great loss to human experience? I couldn't think of introduction really.

Soulstar is a fascinating deed of alternative or just plain wrong culture in which we explore the idea that during normal life sorting out senses and experiences, intelligence and other processes tend to mark bits of senses or whole areas of body, mind, memory as "not to be touched". The patterns of behavior that act as remedies show that we are all perfection. Various conclusions emerge, one among is that acceptance can be a good tool in further progress and another that learning is the pillar of enhancing.
http://www.audiotree.com/Soulstar/soulstarastrology.html