We teachers should have love of benevolence to our students, and affection too.
If you got cross and upset for something a student did, for example he acted out, or spoke to somebody else at a test time, say nothing to the student or students right now, when you feel angry.
At that time you can prompt a bit to that or those students, but wait for longer, for the next day or so, and take the kid when all has happened. You will achieve more with a correction then than quarreling when the wrong thing was just done.
Also every time leave a door open to the student to leave. I mean, when correcting, we can let him say out something about the wrong fact, on his own, by himself; we should listen, listen to the kid. And he will likely realize of the wrong move. / Photo from: advising-pair cals cornell edu