On Teaching: Firm or Mean?

Today I failed to remember the difference between firmness and meanness. There is certainly nothing wrong with a teacher being firm with his students. Firmness, as the word's definitions imply, is an almost entirely positive word. One dictionary says something is firm if it is "resistant to externally applied pressure ... securely fixed in place ... possessed of determination or resolution ... constant and steadfast". These are all qualities that any devoted teacher would want to cultivate. If I want to be the best teacher I can possibly be, surely I would want to be resistant to pressure, unwavering, purposeful, and committed. However, today I crossed the line from firmness over to meanness. I was determined and resolute, but in a somewhat selfish and petty way. I was constant and steadfast, but in a manner that bordered on the malicious. It's a fine line, certainly, between these two attitudes. A teacher can be extremely firm with his students, but still show kindness and graciousness, and just barely avoid slipping over into meanness. Or, a teacher can --and this happened to me today -- turn a blind eye to that thin line and find himself, before he knows what's happened, acting in an almost spiteful manner toward his students. I don't want this to happen again. I want to be a determined and steadfast teacher, but also a considerate and friendly one. I want to push my students, but with a smile and a supportive pat on the back.