Dreams actually do have significant health benefits. Not saying its evolution, but they serve a purpose.

i missed myself on dreaming == sleeping ...

http://en.wikipedia.org/wiki/Dream

amazing

This post was edited by Saucisson6000 on Oct 10 2013 11:17am

Excitation's of Long term memory, Strengthening semantic memories, and removal of excess sensory information, among many other useful things. REM sleep is essential.

any neutral inheritable trait has no reason not to stay in the gene pool

it doesn't have to have a reason if it does no harm, it just happened to be so

It can have both beneficial reason and terrible consequence.

PTSD being one of the latter.

they aren't/weren't commonly hindering people from reproducing

I think it would be massively unlikely that dreams have no evolutionary benefit considering how universal they are among humans. My best hypothesis is that they are a "training mechanism" allowing a person to experience scenarios that could happen in the future, but I think this might be one of many functions. A lot more research needs to be done on dreams before we have even an inkling of understanding.

That's a pretty heavy assumption.

Someone under considerable mental stress would surely be less likely to have success with the opposite sex.

some more info on sleep, short quote from: http://www.bbc.co.uk/news/health-24567412

The brain uses sleep to wash away the waste toxins built up during a hard day's thinking, researchers have shown.
The US team believe the "waste removal system" is one of the fundamental reasons for sleep.
Their study, in the journal Science, showed brain cells shrink during sleep to open up the gaps between neurons and allow fluid to wash the brain clean.
They also suggest that failing to clear away some toxic proteins may play a role in brain disorders.