Understatement is always best. Analogies in writing are like feathers on a snake. The passive voice is to be avoided. Go around the barn at high noon to avoid colloquialisms. Even if a mixed metaphor sings, it should be derailed.
Exaggeration is a billion times worse than understatement.
The Darndest Things Kids say the darnedest things. Some grade school teachers must agree with that, because they keep journals of amusing things their students have written in papers. A census taker is man who goes from house to house increasing the population. Oxygin and hydrogin. Oxygin is pure gin.