butter is meant to be yellow. its fat. fat is yelllow.
Actually, most fat is whitish. I think the color of milkfat depends on what the cow is fed.
what is american bread like?
Well, the standard American sandwich bread has (up until recently) been white bread - slices about 1/2 inch thick of soft white bread with a soft-ish crust. Wonder Bread http://www.wonderbread.com/
is the popular brand(in the South, at least). Nowadays, though, you can find just about any kind of bread. Of course, I live in the city, so I'm probably a little spoiled in terms of diversity.