Older and Meaner

I was totally rude to a customer service guy on the phone just now and I don't even feel bad.  The older I get, the meaner I become, and the happier I am about it.  What is happening to me?  Back in the late 1900's, I was so nice.
Maybe it's because I've done my time BEING the customer service guy to whom customers are totally rude, so now it's my turn to be wicked.
Perhaps it's a rite of passage of being in my forties.  Is forties considered "middle-aged"?  I never really understood what "middle-aged" meant.  How do you know what middle age is when you don't know how old you'll be when you die?
I spent my twenties feeling as though I needed to prove myself to the world, but the world never seemed interested in my provement.  In my thirties I felt the only person to whom I needed to prove myself was myself.  Fortunately, it turns out I'm pretty easily impressed, so once I had reached my forties I liked me so much I quit needing to prove anything and my life got so rad.
Being a girl version of Jeremy Renner, however, is no reason to be poopy to customer service guys.  I should be ashamed.  I'm sorry, Customer Service Guy.