When I first got my CHL I was carrying my Glock 22, IWB at 3 o'clock.
I was working out of town and walked into a local hardware/pawn shop to see if they had any hand tools I could use. The man working the counter (owner?) was with a customer when I walked in. I noticed that he was glaring at me from behind the counter. After the other customer left the man came from behind the counter and walked over to me. He asked "Can I help you?" and made it sound like a threat. The way he was standing told me he was ready to fight. I asked about channel locks or 1/2" ratchet sets or something. I received a quick "NO." I decided I didn't care for the guys attitude and left.
When I reached for my car keys I realize that my shirt had ridden up and my Glock was plainly visible for any who looked. I'm not sure what was going through the shopkeeper's head but he seemed to take a very dim view of open carry.