Q. I am a member of an adult-education foreign-language class where 12 students meet for two hours once a week. The teacher has introduced the charming custom of having a coffee break after the first hour.

When I joined the class, Styrofoam cups were stacked beside the coffee maker. Since I had an oversupply of these cups at home, I brought a stack to class. One member has gotten so enthusiastically into environmentalism that when she saw me putting the cups on the table, she gave me a severe lecture on the subject of landfills, disposable diapers and other unpleasantnesses.

She said she wanted everyone to bring a ceramic mug from home. It was like an order to do so. I told her I didn't want to bother lugging a mug to class every week, along with textbooks and notebooks.

Since she was obviously upset, I searched out a variety store (which wasn't easy) that stocks those paper hot cups that used to be so readily available. Unfortunately the only kind the store had were decorated with patriotic red, white and blue stripes and stars.

I didn't think the artwork mattered, but when the environmental lady saw me stacking them beside the coffee maker, she said, "Why don't you take those things back home and save them for the Fourth of July?" She then launched into another lecture on the subject of everyone bringing a mug from home -- failing to take into consideration the amount of energy it takes to produce just one ceramic mug.

About half the people bring their own mugs; the other half have been wantonly using my gaudy paper hot cups.

I can tell from the grim expression on the environmental lady's face that she is not pleased. I also bought some little red plastic spoons to go with the cups, since class members had been stirring their coffee with knives, which probably aren't biodegradable either.

I realize I'm being anti-environmental, but am I also rude, out of line and ill-mannered?

A. Somebody is being rude, out of line and ill-mannered in this situation. But Miss Manners considers you a model of politeness for having refrained from pouring your coffee on this lady's head.

Self-righteousness, even when the cause is good, does not excuse the intrusion of supervising other people's ordinary lives.

Anyway, Miss Manners suspects that she is bossing others less out of concern for the environment than for her own satisfaction. When you kindly met her first requirement, she moved on to issuing what Miss Manners presumes are aesthetic orders, since it was not claimed that your new coffee cups desecrate the flag. (But then, perhaps, Miss Manners should not be giving her ideas.)

Perhaps it is time to announce politely that you are doing the best you can but prefer to take your coffee break in peace.

Feeling incorrect? Address your etiquette questions (in black or blue-black ink on white writing paper) to Miss Manners, in care of this newspaper.