Stepping on Glass

If you walk barefoot you hear all the time, what if you step on a piece of glass?  Well today I was wearing my minimalist sneakers without socks and I felt a pebble under my foot inside my shoe.  I was getting ready to cross a busy street and was almost at my destination so I ignored it. It rolled around as I cross the street and I kept feeling it under my foot, just a minor annoyance. Once I got inside the building I took off my shoe and dumped out the offending pebble.  Except it wasn't a pebble, it was actually a piece of glass.  Looking very close it appears to have been from a mirror, since I could see the metallic coating on one side.   Below is a picture of the dangerous item.  No damage was done to my foot.

Glass inside shoe - maybe I should walk barefoot.