I was taking a very low dose of xanax for about a year-- I usually wouldn't take more than .5 mgs a day, usually .25, and about half of the week I took none. I noticed about a month in that I was having moments where I would rage with anger, usually for no reason at all or little triggers like if a car cut me off. I tried to follow a pattern and I think it happened mainly at the time that the dose of xanax was leaving my system. So I think that irritability and rage can be a side effect, even in low doses of benzos. At least that's been my experience.