mean teacher face

http://school.discoveryeducation.com/clipart/clip/meantchr.html

I spend so much of my time in "teacher" mode that sometimes I find myself giving the "mean  teacher" face to people over the age of 7 and outside of school. A dentist who was married to a retired school teacher once told me to never treat/talk to your husband like he is one of your students. Now obviously I don't have a husband, but earlier tonight I snapped at my mom and acted like she was a child in my class and I got on to her. Eek! What little defense I have for my actions is she was being mean and talked to me in a rude way. Does that excuse my behavior? No! Did I talk to her in a rude way? Oh, yes! Do I feel bad? Yup.
Do I have a hard time apologizing to people? Yes. :(