A heck of a long time ago when I gained my CPL (now 20 yrs) I was told most forcefully by my Instructor who later owned a SA regional airline,
'If ever you fly any aircraft I own with fare paying passengers you WILL (emphasis intended) look like a professional pilot, and that means collar and tie, wings on your shirt and the appropriate epaulettes!'
'Nuff said.
You only live twice. Once when
you're born. Once when
you've looked death in the face.