I'm proofing a very large book at the moment; it's largely written on the principle that if one metaphor makes writing better, upending a large sack of them over the page makes it wonderful. I haven't kept notes of all the bizarre imagery I've come across ("this powerhouse harbours a stable of...", "prescribes the gold standard", "its depth ... places it at the forefront of the market", seeing an upsurge while in a niche and straddling an arena), but I have to share this beauty. It refers to a lawyer:
"She is easy to talk to and has the ability to boil a case down to the brass tacks."
I have to conclude that most people just don't see metaphors as metaphors. To them 'gamut' and 'spectrum' are just synonyms for 'range', so you can focus on the whole spectrum and straddle a gamut. If someone is at the helm of a company, it's got nothing to do with ships and is not at all incongruous if they're leading the pack.
In reading a little about metaphors, I found that using the verb "to be" makes it a metaphor, but were you to use "like," it is then a simile. The example one site gives is: When Robert Burns wrote "My love is like a red, red rose" he used a simile. When Robert Herrick wrote "You are a tulip" he used a metaphor. That distinction seems very close to me.
It might be a nice distinction but it is an important one as well.
"You are a star" is a metaphor and a compliment.
"You are like a star" is maybe less complimentary since it could mean that you are distant and you only shine at night.
Mixed mataphors, which aput's examples are, can both amuse and confuse and, for that reason, I try to avoid them. After all, if we all put our shoulders to the wheel, keep our noses to the grindstone and pull out all the stops until we see the light at the end of the tunnel - we would probably be dead of confusion before we even started the task.
Yes, I agree, Richard. Especially that metaphor that aput cited, "To boil a case down to the brass tacks," was awkward and confusing. It made me think of a surgeon boiling his poor patient (which they call "cases") down to brass tacks!