Frustrated

Do you ever feel like your words just aren't getting through? You repeat yourself, then use different words...simpler words...complicated words....and the person just doesn't seem to be getting it?
I have decided he's just being purposefully obtuse. I know he understands the words. He just chooses to ignore them..ignore their meaning...ignore the conclusions to be drawn.
It frustrates me to the point of aggression. And then I feel the fool for losing my cool.
Today stinks :/