And then, on the other hand...

...I have students who give me little presents to say thanks for all the help I've given them. The girl in question worked really hard all term to master the subject matter (pushing herself tirelessly beyond an ESL handicap), and I think the improvement is really clear.

I can be proud of what I helped her to accomplish; and thus, teaching shows itself to be - like all things in this world - a double-edged sword.