One thing I know is that Americans love sauces. Take something white like potatoes, chicken, bread and soak it with some type of sauce.
I make sushi for a living and I've seen people put ketchup on them. I find that to be very low-class or maybe even narrow minded.
I'm not and was not trying to attack Dogmatic on this one. Put ketchup on it if you want. My point was - lets look at how the food is prepared.
We'll take sushi for example. Firstly, the word Sushi simply refers to vinegar+rice. That is what sushi is and has been for over a 100 years. The improvisation and the cultural fusion is done with adding different stuff with the sushi. NOT using brown rice because you're on a low-carb diet or some other bullshit. The white rice sticks, that stickiness keeps the rolls and the nigiris intact - THAT'S SUSHI. The vinegar used isn't plain vinegar. Various indgridience are mixed for better flavor - this depends on the restaurant but I would say the vinegar alone has about 7 different tastes fused together. Then of course you have the wasabi which adds the wonderful tasteful kick. Some fish has natural flavors that will taste fine without any additional flavoring - others require a tiny bit of soy sauce.
So, you got this eatable works or art in front of you with lots and lots of flavors with-in it. Do you really want to shit on it by pouring ketchup on it and erasing those flavors? I hope not. I don't bust my ass so you can enjoy ketchup rice.
Chicken is bland. We know this. Yeshua had a thread about it not too long ago actually. It would make sense for someone to use ketchup. But I believe in alternatives - that's why I mentioned the words "marinated" along with "garlic butter". Let the chicken marinate for an hour before you grill it. I prefer soy sauce with mirin (or other sweetners.. maybe honey). throw some finely diced garlic and ginger and BAM.. you get a simple grilled chicken with good flavors. And the garlic butter of the asparagus adds a very nice touch.
As far as the sushi goes - i don't know why people want to put ketchup on sushi, it looks silly and almost offensive from my side of the counter.