it would be bad to be lucid back when you had to hunt for food and water.

the reason being: If I had the choice to a) go to sleep and enter a world where I could have all the cooked wild buffalo I wanted just by thinking it or B) get out of the cave and enter a cold harsh environment where I had to spend hours upon hours hunting down a buffalo that tasted worse than the one i could have in the LD I think i would go with the dream.

the same more-so goes for sex.

If we had lucid dreams back then we wouldn't be around anymore