The Watchers Council had made certain promises. First, that Rupert Giles would have no trouble getting his cover job as the new school librarian at Sunnydale High School. Second, that this role would require minimal actual librarianing, which was a good thing, as he had been rather distracted during his library studies coursework what with all the simultaneous advanced Watcher training. And third, that he would not have to deal with teenagers other than the Slayer herself.
The Watchers Council had lied.