We've all seen this. The team leader says, "We'll begin the project in February." Immediately one of the staff says sarcastically, "Certain of that, are you?" and ten others in the room smirk. The team leader now replies, "Yes, as certain as we can be" as if she had not noticed the sarcasm.
Not a single person in the room misses the fact that the team leader could not handle the emotional message behind the words - the real message. Her credibility goes through the floor.