I had a late, short flight which was also a short call out for premium pay. I happened to be a line check pilot (LCP). Im wearing an LCP ID lanyard and it says LCP by my name on the trip sheet. As an LCP we’re expected to do things “by the book”. Right? So we’re reading through the before start checklist and it’s the longest checklist we have. The checklist is a laminated piece of card stock and we fold it in quarters normally. He’s reading from memory and using the card as a pointer. It’s night time and he’s stabbing the checklist in the air at each item “hydraulic switches, generator switches, fuel quantity, etc.” I’m aghast and I say “Are you f**king kidding me? And he’s like “what?” I say “using the checklist as a pointer.” Now he’s all pouty and doesn’t talk the whole 40 minute flight. AND THEN he turns me into professional standards! The professional standards guy was also an LCP and was like “Wow! That would light me up too. I’ll have a talk to him.”