Lets say, just as an example, Barack Obama and George Dubya Bush meet up one night and they go to the Olive Garden for some spaghetti with three cheese marinara, salad, and breadsticks.
The next morning, news headlines (newspapers and online) might look like this:
OBAMA, BUSH EAT SPAGHETTI AT OLIVE GARDENWhats with the comma? Any time I read an American newspaper or website, and they're talking about two or more things/people, they never say:
OBAMA AND BUSH EAT SPAGHETTI, or BUSH & OBAMA EAT SPAGHETTI.... its always BUSH, OBAMA EAT SPAGHETTI
Who taught you people that? Its awful!

(I do realise there are more important issues in the world. I'm just killing time before dinner)