Now!

Out of your whole life give but a moment!
All of your life that has gone before,
All to come after it, -- so you ignore,
So you make perfect the present, condense,
In a rapture of rage, for perfection's endowment,
Thought and feeling and soul and sense,
Merged in a moment which gives me at last
You around me for once, you beneath me, above me --
Me, sure that, despite of time future, time past,
This tick of life-time's one moment you love me!
How long such suspension may linger? Ah, Sweet,
The moment eternal -- just that and no more --
When ecstasy's utmost we clutch at the core,
While cheeks burn, arms open, eyes shut, and lips meet!
(Robert Browning ... mid 1800s)

It seems as though not all understand why, but the following quotes should clear this up. The simplified answer? It is pleasing to the Frees.

It reminds a girl in her service that she is personalizing her serve. she makes every effort to stand out. she makes every effort, as small as it may be, to be pleasing. her voice carries her feelings. her feelings will be expressed in her serve. The Free men find it pleasing. And, it is expected that a girl show the one she serves a true desire to serve.

For her, to offer a different phrase with her serves, gives the girl the chance to show that she is skilled. As small as it may be, she doesn't come off as being repetitive, same thing all the time. she spruces it up, adding a different phrase with her serve as often as she can in hopes to be found pleasing. hazine, for one, didn't realize how important this is with something so little until she searched through her scrolls and knelt back wondering, as she reread these. slaves learn something new all the time. her learning and training is neverending.

Is it now, only a small gesture?

I, carrying the crater, rose to my feet and approached him. I then knelt before him, with a rustle of slave bells, in the position of the pleasure slave. I put my head down and, with both hands, extending my arms to him, held forth the wine crater. "I offer you wine, Master" I said. (Captive of Gor, pg 331)

...But I did not take the paga. "Do you know other phrases?" I asked. There were many, actually, and they tended to vary from tavern to tavern, and from city to city. There was, really, no standardization in such matters.
She trembled, head down, proffering me the paga.
"Your girl brings you drink, Master," she said.
"Any others?" I asked.
"Here is your drink, Master," she said. "I beg to serve you further in any way I may."
"Another," I said.
"Do not forget I come with the price of the cup," she said. "Use me as you will, Master."
"Another," I said sharply.
"Personalized phrase," I said.
"E.," she said.br> "Evelyn," I corrected her.
"Evelyn tenders drink humbly to Master," she said. "Evelyn hopes Master will later find her suitable to give him pleasure."
"Another," I said.
"I am Evelyn," she said. "I serve you, naked and collared. Take me later to the alcove. I beg to be taught my slavery."
I then took the paga. "You may now serve others," I said to her." (Explorers of Gor, pg 161)