Don't get your knickers in a twist

I know I've said this before but people really need to know what words really mean when they use them.
Let's use the word 'literally' - the Oxford English Dictionary definition: 
Literally - adverb
In a literal manner or sense;exactly.
EXACTLY. That means WITHOUT exaggeration.  So when your friend tells you 'Oh my god I literally peed myself laughing' that sentence really means they actually urinated while they were laughing.  Which hopefully, was not the case. 


Also, why do people say things like 'keep your hair on' and 'don't get your knickers in a twist' when you get mad?
Do you know anyone who stats twisting their underwear when they get fustrated?  How would they even manage to do that?!  And keep you hair on? ON? as if my hair where simply placed on my head and very easy to remove?  Yes, everytime I get upset, I remove my hair - because I can do that.  My God.