I ran a few miles around a 300 meter middle school track years back and I felt something hurting or scratching in my shoe. I ran through it and finished the run. When I took my shoe off afterward my sock was bloody and I looked into the shoe to see a staple sticking up from the bottom of the shoe which had been pricking me the whole time. I brought it back to the store with blood on the inside and they replaced the shoes for me.
Any of you have experiences like this?