A friend of mine claims Fahrenheit is more convenient because of "-ties". "Today it will be in the fifties/sixties/thirties/high seventies." Celsius doesn't have conveniently-spoken ranges that give users a general idea of the weather. I countered with high and low teens, low twenties, but I don't think his point is completely invalid.
You say centimeters are better for small things and meters better for large things, but neither are very useful for things that might constitute an arm-load. I'm not sure that sentence is very clear, so I'll try examples. My laptop is 36 centimeters wide, which is an inconveniently large number of units for it to be, but it's only a little more than a foot. This textbook: about a foot square. That hard-drive is half a foot (I'll admit that "six inches" was easier to the tongue, but in reality it's closer to seven, which I wouldn't say). What I'm trying to say is that the unit "foot" is very convenient for things that we might be handling in everyday situations, unless those things are hand-sized.
...is your preferred unit bigger than a breadbox?
What's a breadbox? How big is that?
Well...I've never seen one, but...It has to be bigger than a loaf of bread, right? Otherwise, the bread wouldn't fit inside. And it can't be big enough to hide a body in, or it would definitely be named for that property. So mid size-ish.
If that's all you know, why the hell are you using it as your basis of comparison?
It's just so convenient and fun to say!
Today my coworker Marcello pointed out to me an interesting anti-majoritarian effect. There are three major interpretations of probability: the "subjective" view of probabilities as measuring the uncertainty of agents, the "propensity" view of probabilities as chances inherent within objects, and the "frequentist" view of probabilities as the limiting value of long-run frequencies. I was remarking on how odd it was that frequentism, the predominant view in mainstream statistics, is the worst of the three major alternatives (in my view, you have to presume either uncertainty or propensity in order to talk about the limiting frequency of events that have not yet happened).
And Marcello said something along the lines of, "Well, of course. If anything were worse than frequentism, it wouldn't be there." I said, "What?" And Marcello said, "Like the saying that Mac users have, 'If Macs really were worse than Windows PCs, no one would use them.'"
At this point the light bulb went on over my head - a fluorescent light bulb - and I understood what Marcello was saying: an alternative to frequentism that was even worse than frequentism would have dropped off the radar screens long ago. You can survive by being popular, or by being superior, but alternatives that are neither popular nor superior quickly go extinct.
I can personally testify that Dvorak seems to be much easier on the fingers than Qwerty - but this is not surprising, since if Dvorak really were inferior to Qwerty, it would soon cease to exist. (Yes, I am familiar with the controversy in this area - bear in mind that this is a politically charged topic since it has been used to make accusations of market failure. Nonetheless, my fingers now sweat less, my hands feel less tired, my carpal tunnel syndrome went away, and none of this is surprising because I can feel my fingers traveling shorter distances.)
In any case where you've got (1) a popularity effect (it's easier to use something other people are using) and (2) a most dominant alternative, plus a few smaller niche alternatives, then the most dominant alternative will probably be the worst of the lot - or at least strictly superior to none of the others.
Can anyone else think of examples from their experience where there are several major alternatives that you've heard of, and a popularity effect (which may be as simple as journal editors preferring well-known usages), and the most popular alternative seems to be noticeably the worst?
Addendum: Metahacker said of this hypothesis, "It's wrong, but only sometimes." Sounds about right to me.