When listiing files using "ls -al" in terminal, I noticed that some ordinary documents had their x flag set while other did not, even though created by the same program e.g., Word. For example one file had permisions "-rwxrwxr-x" and another had "-rw-rw-r--". I thought the x flag was only for executable files? Is this a permissions error? Will it cause any problems? If so, what's the best way to fix it?