I can understand how irritability can be a sign of mania, but I hate how that means if someone with bipolar is irritable that MUST mean he/she is manic.
I'm often irritated as well, but most of the time it's not even because of mania. It could be from PMS, a bad night's sleep, stress, or a billion other things. Just because I lash out once in a while doesn't make me manic.
However, when I am manic I do experienced a more severe, consistent irritability. If I'm still frustrated with everything even after running 10 miles and am acting out more, I know that's associated with the mania.