your own feet
I don't know, but I love tripping into a big pile of bagged trash. Gives me the perfect excuse to satisfy that paraphilia in public, even if just for a little bit. I always act a bit injured so I can stay in the trash for half-a-minute at most.
I'm not bothered about going to a landfill, believe it or not. A nice full dumpster does me fine. Something that I never fail to look forward to, when the opportunity arises, is visiting the big dumpster of a local office complex and spending hours among the numerous bags of office and cafeteria trash while wearing a poopy diaper. And only a diaper -- and sneakers, that's it! Wonderful thing to do during the early morning hours when it's suitably warm out! :-)
I tripped over my own feet and a kerb/paving slab/cobble once
I tried to jump over a guide wire and caught one foot and did a nose dive. Scraped up my nose and chin.
bananna peel of course
Your own feet
my own two feet.