Dirty Cups

My mother taught me to clean the inside of a cup so that coffee and tea stains would not remain.  Clean the inside and the outside would be fine.   Don't be lazy and clean only the outside of the cup. At the monastery we each have our own cups which sit on a shelf with our name under our cup. I always clean the inside of my cup to this day.  But sometimes I will use a cup from the common stock of cups stored on the coffee cup shelf.  Stains on the inside of the cup!  I say, "Useless and worthless monks!"  My attitude is one of resentment and judgment.  If so, then maybe I ought to be cleaning the inside cup of my soul, and not just trying to look good on the outside, or focusing only the others and their perceived shortcomings.  Did not Jesus say, "Clean the inside of the cup, so the the outside also may be clean."  My daily spiritual life needs to focus on my insides or else I will be ever resentful and judgmental of the world around me.