I'm fascinated by decay and rebirth. And dirt is where it happens. I've been composting for years---taking overripe fruit and unused ruffage and turning them into good healthy soil. (Although, strictly speaking, it's the micro-organisms that are doing the actual work.)
Anyone can compost; and everyone should! While it's certainly easier if you have a yard, there are ways to make it work even for people stuck in tiny apartments. (Some resources for apartment dwellers here.)
Most things will break down eventually. But some things take too long to be practical; and others contain substances that are pretty harmful to soil---not to mention the people who may eat plants grown in that soil.
Technically, animal products like meat and bones can be composted, but they tend to attract hungry critters who will be tempted to get into the compost. In addition, there's a small chance of health hazard.
Personally, when I kick off this mortal coil, I hope to decay the old fashion way. I'd be happy to become part of my own compost pile. No stinky formaldehyde for me, please!