A friend of mine referred my resume through a referral program. A Principal Software Recruiter reached out quickly, with a very formal letter and we scheduled a call. On the day of call, however, he called me 25 mins early, didn't introduce himself or apologize. When I asked him why he is calling early, he said he have another meeting scheduled, in a quite annoyed tone. At this point I told him that I have changed my mind and he answered "that's fine" and hanged the phone.