Phrases

Now, before I start the actual topic, I'd like to say that I come from a pretty unintelligent area.  Very few people here can pronounce any words correctly.  Now, having said this, most of my problems understanding some phrases were due to incorrect pronunciation.  I didn't even know what the phrase ''once in a while'' meant until I realized it wasn't ''once in a wow.''  The mispronunciations were just that bad.  I'd now like to move on to other phrases that don't make sense to me.  A good example of this is ''brain fart.''  At least when it's used with its proper definition.  Its proper definition is when you can't think of an idea.  Not even a bad one.  I think it should mean when you can only think of bad ideas.  Then again, most people have that quite often.  In the sense they use brain fart they should be using mental block.  Mental block makes sense to me.  It means your mind has been blocked from forming any thoughts.  Now, if my definition of brain fart becomes vocalized, it's called diarrhea of the mouth.  I'm not sure about you, but all of this concern about the shared lower anatomy of the human species disturbs me a bit.  I mean, most of our society is disturbed by nasty things, so why do we have such an obsession with such things?  Granted, I don't find them nasty, but most people do.  I'll never understand why we have such an obsession with things we find so disgusting.  Then again, it could explain the two girls one cup phenomena.  If you don't think about it too much, that is.