It's not unusual (=it is quite common)to feel very angry in a situation like this.
WORD CHOICE: WORD CHOICE: unusual, strange, odd, bizarre, extraordinary, exceptional, remarkableUnusualis neither approving nor disapproving• a suit made of unusual material • an unusual name • Her response was unusual.Strangeandoddmean unusual in a way that you cannot understand. They are sometimes used to show slight disapproval or distrust• a very strange man • I found his attitude a bit odd.Bizarremeans very unusual, especially in a way that you think is amusing or that is hard to believe• a bizarre haircut Extraordinarycan be approving or disapproving, but suggests approval when it is used to describe a person• What an extraordinary idea! (can suggest you strongly disagree)• My mother was an extraordinary woman (=very impressive, talented etc).Exceptional and remarkableoften mean unusually good or impressive• a writer of exceptional talent • a remarkable film
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.