I've couple of files that I cannot remove using rf -Rf command. I'm the owner of those file and the group assigned to those files is also a group my user is in. What's even weirder is that I can edit their content and I can change the permissions for them, but I can't move or delete them.
Don't forget the use of "lsattr" and "chattr" command line...
:~/temp$ touch pippo.txt
:~/temp$ ls -la pippo.txt
:~/temp$ -rw-r--r-- 1 root root 0 2014-03-13 16:35 pippo.txt
:~/temp$ chattr +i pippo.txt
:~/temp$ lsattr pippo.txt
:~/temp$ ----i-------------- pippo.txt
:~/temp$ rm pippo.txt
rm: remove write-protected regular empty file 'pippo.txt'? y
rm: cannot remove 'pippo.txt': Operation not permitted
:~/temp$ sudo chattr -i pippo.txt
:~/temp$ lsattr pippo.txt
:~/temp$ ------------------- pippo.txt
:~/temp$ rm pippo.txt
:~/temp$ ls
:~/temp$