I cry. I've cried in all kinds of situations. The pressure was huge at times.
I've got the talent for having tears stream down and being able to continue in a calm voice to say what I have to say. At least I don't unravel completely.

I've managed not crying in front of customers so far, which is excellent, but I don't think the advice just not to do it is a feasible way to go for those who are built too close to water.