A Smile From Now Til Christmas

Today I went to the phone store to get mine fixed. I saw an old guy sitting down with a bunch of empty chairs next to him. Although I normally would have given myself a good 3 to 4 seat barrier (no need for uncomfortable interaction with strangers) for some reason I decided to sit right next to him despite the long row of empty chairs. Here's what happened (the stuff in parenthesis is non-verbal inner dialog):

OldGuy: Can I give you something to smile about from now til Christmas?
Me: (He seems harmless enough but with a statement like that things could get really creepy really fast) Sure, I would love to have something to smile about. I am sitting here with a broken phone.
OldGuy: Chuckle...Ok, pick a number between 1 and 10. Now don't tell me just keep it in your head.
Me: Ok, got it (7)
OldGuy: Now double that number
Me: (14)
OldGuy: Ok now add 4
Me: (18)
OldGuy: Now give me 1/2 of the total and you keep 1/2 of the total
Me: Ok...(9)
OldGuy: Ok now take your half and subtract your original number (9-7=2)
Me: Got it.
OldGuy: Now tell me, how many beautiful people are there in this conversation? (Eyes smiling)
Me: 2!!! There are 2 beautiful people. How did you DO that?!?
OldGuy: (Laughing) Everyone always knows what a frown is about but if you are always smiling then you keep 'em guessing.

My new friend then left to pay his phone bill. On his way out the door he walked by and grabbed my hand. He looked me right in the eye and said, "Remember, patience is a virtue." I thanked him for the smile and he left chuckling to himself.

How did he know I needed a smile AND some patience???

p.s. When I got back to work I tried the riddle with 2 other numbers and it still worked... :)