Lack of Proportion

Either exaggerating or downplaying a point that is a crucial step in a piece of reasoning is an example of the Fallacy of Lack of Proportion. It's a mistake of not adopting the proper perspective. An extreme form of downplaying occurs in the Fallacy of Suppressed Evidence.

Example:

Chandra just overheard the terrorists say that they are about to plant the bomb in the basement of the courthouse, after which they'll drive to the airport and get away. But they won't be taking along their cat. The poor cat. The first thing that Chandra and I should do is to call the Humane Society and check the "Cat Wanted" section of the local newspapers to see if we can find a proper home for the cat.

Exaggeration

When we overstate or overemphasize a point that is a crucial step in a piece of reasoning, then we are guilty of the fallacy of exaggeration. This is a kind of error called Lack of Proportion.

Example:

She's practically admitted that she intentionally yelled at that student while on the playground in the fourth grade. That's assault. Then she said nothing when the teacher asked, "Who did that?" That's lying, plain and simple. Do you want to elect as secretary of this society someone who is a known liar prone to assault? Doing so would be a disgrace to the Collie Society.

When we exaggerate in order to make a joke, though, we aren't guilty of the fallacy.