Earlier this year, an experiment was conducted. 200 unbranded USB drives were dropped in high-traffic public areas in Chicago, San Francisco, Cleveland, and Washington DC. 20-percent of those who found the USB sticks picked them up and just plugged them right in to an electronic device. The users then proceeded with clicking on files and browsing to websites.
Okay, "people are stupid" isn't necessary a newsflash but let's go ahead and say that you might not understand why this is a risky behavior and, in fact, you don't see why sticking USB sticks in computers is a problem.
USB sticks are unencrypted storage devices that are read by computers when they're "mounted", or, inserted into a USB port. When that happens, it's possible that the USB drive can deliver a virus to the computer. Further, the files found on the USB drive can be double-clicked or opened, allowing for a virus to then launch on the infected computer. Finally, browsing to websites introduced by a USB stick could also introduce a virus to your computer.
Viruses, naturally, can then steal personal private information or harm your computer system.
Why did the stupid people do this? They wanted to see if there were any naked pictures on the drive, of course, or, wanted to invade the potential privacy of others by looting their personal files. They also wanted to see how big the drive was to see if they wanted to keep it for themselves, because people are greedy pigs. And finally, they just weren't trained not to do so, or, didn't care about the potential security risk - simply ignorant. Peoples do as peoples does.
So two take-aways here:
1. Don't store your crap on USB drives. It's an insecure medium and can easily fall out of your control, leaving your data to the sex-starved, greedy, ignorant masses.
2. Don't be stupid. Don't take any unknown USB drive and stick it into a computer you own, or, your work computer. Naturally you should do it on your friends computer or you mom's or something, but if you're not going to be a jerk about it, just throw it away. Well, okay, e-recycle the thing.