I avoid unergonomic / "low-usability" food, that is, anything with inedible elements like bones, cartilage, shells, scales or fruit stones, or just hard eat. Examples include chicken, bony fish, shrimps, cherry, watermelon (though I've recently found a way to deal with watermelons safely), and generally unwieldy food like this hamburger.

Why? Because I just want to eat the food, not to "deal with" it. Also, when I eat, I prefer my hands to be dry and clean, so when I deal with messy food, it is not uncommon for me to go wash my hands in the middle of a meal.

Not very strictly. I'll eat such food if it's served by my host or when I'm hungry -- though I won't order it at a restaurant if an ergonomically-safe alternative is available.

Speaking of children, the only thing I'm really concerned about is safety -- e.g. I avoid giving my four-year-old daughter bony fish unless I pre-process it myself.

No, never tried.

In my case it's easy -- I just replace it with a less messy / higher-usability dish.

Indifferent.

I've had these restrictions since childhood.

I do enjoy the taste, I just don't like the process.

I'm a meat eater, but I'll switch to in-vitro meat as soon as it becomes available.