What Do You Do With a Tennis Player With Three Balls?

It's Wimbledon time again.  As a borderline tennis fan, I'm always filled with questions during any major tournament.  Like what is an Unforced Error, and why does no one count Forced Errors?  Why is Andy Murray considered one of the "Big Four" Men's players?  Yes, I know, he is one of the top four male tennis players in the world, but isn't that sort of like counting the company that makes Oscar Mayer Wienermobiles as one of the Big Four American car companies?

But right now I'm wondering about one of the odd practices of the game.  Before a serve, one of the ball boys/girls will give the server three balls.  The server stares at the three balls for a second, tosses one aside, puts another in his pocket, then uses the other.  So I'd like to know:

• What is he looking for?
• Why is it than in any group of three balls, precisely two will have it?
• How come the players can tell, but the ball boys can't?
• Why put one in your pocket?  You have these speedy servants hanging around you, they could just give you a new ball as soon as you need another one.  I mean sure it's a great power trip to have these balls presented to you just so you can reject one, but wouldn't it be an even better privilege to miss your first serve, angrily snap your fingers, and have a servant run out with another ball?

It gets even weirder in the Women's game.  They don't have pockets, so what do they do with the extra ball?  Shove it up the side of their skirt.  Where are they putting it?  A lot of the women in tennis go to great lengths to appear stylish on the court; doesn't it occur to them that no amount of jewels or designer outfits can make up for the appearance of a giant growth on their hip?