It would be rude, my Kenyan priest friend tells me, to invite someone over to your house and not take a bite before your guests do. It comes from a tradition suspicious of poison, he tells me. The host eating first indicates it is safe and good to eat. What kind of message would it send, he asked laughing, if I served you food and then didn't take a bite to show you it was good? This cultural etiquette was behind his shock that the priest in our seminary chapel doesn't always take the communion first before serving it to the congregation.
From my view, the priest that
does serve herself first is suspect. It smacks of clericalism.
Wait, watch me while I eat this. I did this important thing; and now I will eat this important thing. I'm going to take the cynical view that everything you do in Episcopal worship is going to piss someone off. Hold on, there. Am I projecting? :)