I just asked my kids.
According to my 18 year old son: I am not difficult, but his father is. (They butt heads a fair bit.)
According to my 20 year old daughter: Neither of us are difficult.
According to me: My mother is incredibly difficult. I'm passively avoiding her right now.
And my mother-in-law is didn't used to be difficult, but is currently. It's not her fault, she's incredibly sweet and awesome, but also terminally ill. Dying sucks.