It is basically just discourteous. Don't be an academic leech. Other students soon learn to dislike those who don't go to class but always want to borrow notes. If you want to have friends, don't take advantage of them. Makeup exams, if allowed, are commonly more difficult than the original.
Zeros absolutely kill an average.
Follow up on everything - transcript requests, graduation applications, scholarship applications, etc. It is too important to assume that these things have been properly processed. Call and check. If it isn't important enough to be on the exam, it probably isn't important enough to mention in class. Asking this makes you sound like a dolt that is only interested in getting a grade.