True to you

Today my son got picked up by his father who gets him about once a month for a week or so.  In seeing him again, it immediately brings up old issues.  Why is it that I care so much about what people think?  I mean, I was self conscious of my home and how it looked because we're in the process of moving.  Things were thrown everywhere and it was a mess.  I immediately thought about what he was thinking.  Why should it matter?  When we were together, the house was never clean enough for him.  He always had a problem with what I did.  So, my question today is, why do we care about what others think?  No matter who you are or who your person or people are that you want to impress, I want to know, why do we care?  Chime in please.