Irritability, an agitation that may result from provocation, illness, or seemingly no reason at all, may be simply an expression of normal annoyance, but it may also indicate a mental health or medical condition. When experiencing consistent irritability that causes stress and interferes with the ability to sleep, work, eat, or maintain good relationships with others, or irritation that may be inappropriate for or out of proportion to a particular situation, it may be helpful to speak to a therapist.