Code:
import shutil

files = os.listdir("C:\\")
for efile in files:
    shutil.copy(efile, "D:\\")
I didn't think this simple script may crash whenever C: and D: are available and permissions are given, until I ran it on a pc with files named with unicode characters!

Python converted these characters into question marks "????" when it got the list from os.listdir, and...