It's inevitable that I'll have to leave my section from time to time. Sometimes I'm running food for other waiters, singing birthday songs, looking for coasters, etc.
A lot of times, if there is food getting backed up in the window I'll run it for the other people so that I can get to my own customers' food. This is where problems arise. If I'm passing by you with a tray you should notice at least two facts. (A) I'm not your Waiter, and (B) I'm very busy.
That being said, one would assume that I have my own customers to deal with. I have orders that need to be taken and rung in, salads and entrees that need to be delivered, desserts to make, bills to drop off and collect. So no, I am not getting you another beer or appetizer. I can't ring those in for you anyway. I'm not even going to get you more salad dressing. I may refill your water if I'm feeling generous. I may make promises of bringing you more napkins and then promptly forget. That is your server's job. My customers are paying me for service. I couldn't care less about you as you're not paying me. Ask your own waiter.