When I was a kid growing up, I would often help my dad with various projects around the house.  Especially at first this mostly involved me standing around a lot and running and getting him tools and supplies when asked, and one of my earliest memories of fetching a tool for my dad was getting him a hammer.  I went down into the basement and grabbed the nicest looking hammer and came running back with it.  "Oh, no, sorry, but I wanted your grandfather's hammer--the one with the brown leather handle," he said.  "Could you please run and get that for me instead?"  I was perplexed.  I knew the hammer he was talking about, and it was a rusty, beat up looking thing with a weird handle!  Why did my dad want THAT hammer?  Just because it had been his dad's maybe?  I didn't know, but, I ran down and got him that hammer instead.  I soon learned that when my dad wanted a "hammer" he wanted THAT hammer--evidently his favorite hammer.