It's Jack...Just Jack

I've been struggling with people calling Jack Jackson.  We specifically named him Jack, not Jackson and it irritates me that people just assume his name is something other than it is.  If I introduce you to my son and say his name is Jack, why would you think it was anything other than that.  I can kind of  understand when people shorten someone's name like Elizabeth to Liz, but why would you make it longer?

Anyway, so I got up this morning decided to try and rectify the situation.  I got on my dear embroidery machine, Bernie, and made Jack a special shirt that says "Just Jack".  Passive aggressive?  Maybe. You decide?