One should never generalize. Comparisons are as bad as cliches. Leave that to the US Department of Redundancy Department, whom we support with our tax dollar support. Be more or less specific. Understatement is always best.
Exaggeration is a billion times worse than understatement.
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.