Why is the stuff that is funny when you are stoned or drunk not funny when sober?

That's the reason for getting stoned/drunk.

Otherwise it wouldn't be fun to do either.

because when you're sober you're too occupied with societies view of you - you're controlling yourself to make sure you appear to agree with society, therefor you're not on the "out".

runningtaveler wrote:

because when you're sober you're too occupied with societies view of you - you're controlling yourself to make sure you appear to agree with society, therefor you're not on the "out".

Well, yeah I'm not gay but good reasoning.

My understanding is that one of the changes that alcohol causes in the brain is increases in the effects of GABA (gamma aminobutyric acid). GABA keeps anxiety and hypertension down and sex drive up. One theory is that alcohol increases activity between GABA and receptors, causing us to relax (and some people to tap anything that moves). Lower anxiety probably equals more laughing. I don't know much about THC, but it might be similar.