Reason for smacking someone on the ass?

If I could communicate out loud the way I talk to myself inside, I would either be rich, dead, or in a mental institute. ( I'm guessing either of the last two would most likely be the outcome, but you never know.)  Now see, that in parenthesis was me talking to myself.  Anyway, I was going over this phrase people like to use (alot) in my head the other day.  "Everything happens for a reason".  UGH!!!! I used to hate that saying!  Now, I'm sure alot of people will want to punch me out for putting this thought into your heads "Everything really does happen for a reason, no matter how awesome or shitty it is."  And the fact is we may never know the reason other than it is to teach us something.  Example:  I remember being 5 or 6 years old and going to McDonalds with my mom and brother Chris.  I specifically remember whispering in her ear," DO NOT GIVE THE SCRATCH OFF TICKETS TO CHRIS" and she promised she would not.  Me and Chris sat down at a table and waited for her to bring the food and MY tickets.  All of a sudden my brother jumps up from the table running up to mom, who was still at the counter.  What do you know, that son of a bitch came running back like he was in the 100 yard race waving those tickets in my face.  He was SO proud of himself, bless his little heart. NOT!!.  Being the Taurus that I am, I stood up with smoke billowing out of my nose and ears and charged toward mom.  Her back was to me and I proceeded to rear back my hand and smack her on the ass as hard as I could.  She turned around and gave me the "when we get home" look.  Don't even remember what happened when we got home but I do know I will NEVER forget that experience.  I can still picture it so clearly in my mind.  Now I have to ask "what was the reason for that?"