Why the hell do guests at restaurants ask the bussers to get them a refill or hot chocolate with whip cream?

Today was my first day as a busboy, and I had a lot of fun...

One thing that confused me was when a guest asked me to get them a refill or just give them some hot chocolate. I'm thinking to myself, "I'm a busboy... I clean up after other guest's shit... You want me to get you a hot chocolate with my dirty hands?"

And then you complain about the place being unsanitary (the restaurant is clean for the most part).