When I was growing up, I spent a lot of time looking down. Mostly, it was shyness. I was always told that I should look up -- that it didn't do one good to spend all the time looking at the ground.
However, looking down has a real advantage (other, of course, that avoiding people staring at you) and that is that you find "stuff". Quite apart from having fund a lot of money this way, I find bits of jewelery, broken pieces of pottery, marbles, beads, driftwood... the flotsam and jetsam of other peoples' lives.
Of the things I find, some regularly found objects are: marbles, religious medallions, animal teeth, porcelain drawer pulls, and (on one particular beach) shards from old clay pipes and arrow heads. I have a whole box of the latter.
When I lived in New York City, the beach on the end of our street provided great finds on a daily basis. There, amongst the medical waste, I found porcelain doll heads; shards of recognizable 18th and 19th century pottery; beach glass, including decanter tops; and porcelain drawer pulls. There were also many unidentifiable but intriguing stone and wood objects.