I know part of why I get so agitated at her.  She has this way of acting like she doesn't know how to do something or doesn't know the answer that just gets under my skin.  Her ultimate goal is to make me believe that she can't do it so that I do it for her to "show her how" or frustrate me enough that I will do it myself.  It used to work.  Now, not so much; but it is still extremely annoying.  She will drag a simple job out all day long.  She will nag her sister until M "helps" her do a job and then end up only doing a small portion of it because she works slower.  It goes back to what agitated me first thing this morning:  she is manipulative.