Folder with dot file shows as empty
In file (nautilus), if you do not show hidden files, and open a folder without other file it happens as "Empty Folder", so if you are not aware that there is the possibility that some hidden file is inside, you delete it, without caring. and this could be very problematic.
Example: create a folder, and open it in nautilus, it shows as "empty", then go in the folder with the terminal and do a "touch .test", in Nautilus it is still showed as empty. Of course it shows the hidden file if you select it in the menu, but there is no indication that there are file in the folder if you request to delete it. In particular if you activate the "delete definitelly" without going through the trashcan.