I found most of your points absurd and you were up voted up so I thought it warranted a hopefully proper response.
My country (Sweden) has used the metric system by law since 1888 so there's nobody left that remembers the good old days, it's something even the oldest of our grandparents were taught in school.
Metric is worse in almost every way for day to day tasks. Not everyone is a scientist doing complex calculations. For science, maths, engineering, sure use metric.
Considering that every day people in my country and every other country that uses the metric system (almost the whole world mind you) is as normal and ordinary as every other place on earth I really don't see the point of what you are arguing. Even the most incompetent people I meet seem to be perfecly able to do extremely trivial calculations like they are second nature.
Imperial measurements are based on convenience. Why do we buy a dozen rolls from the baker and not 10? So we can divide them between 2,3,4,6 people.
We still say dozen and buy eggs in the dozen (or two dozen). The system for measurment you use do not force you to stop buying in convenient amounts. The only time I notice problems with dividing edibles is when there's children around or someone is trying to figure out how to slice a cake into an odd number of pieces.
Weights are similarly based on what is useful. Look at a recipe for cakes and you might see 1Lb of this, 1/2Lb of this. The metric equivalent? 100g of this, 200g of that. How is that more useful to me?
It's not more or less useful, it's exactly the same level of usefulness.
Why do we ask for some 2 by 4 timber? Because it's easier than asking for some 48mm by 96mm timber.
I would write your question exactly the same way but with 5 by 10cm instead of 2 by 4 though I honestly have no idea whatsoever what unit you are using to make the decimal equivalent. nevermind I figured it out it's probably " which means inches except it gives me slighter larger numbers when I put in "2 inches in cm" into Google it's 5,08cm. You would also probably ask for a slightly larger piece of timber for the same reason as you wouldn't ask for 1.9 by 3.9 of timber. Then again I'm not an arts and crafts type of guy, maybe there's a convention here I'm missing that's used even in countries that have the metric system.
If you're doing finer work, measuring things in divisions of an inch makes perfect sense. 16ths of an inch means you can subdivide with ease. Try dividing a cm into 8 equal parts sometime and tell me how you get on
Do you somehow manage to get cut things with infinite precisions? You do realize you can use decimal points in the metric system, calculators and that it's no different than the scenario where you split an inch into 7 which I'm sure isn't a problem for you, right? Also since an inch seem to be defined to be exactly 2.54 cm 1/8th of that would be exactly 0,3175cm the scenario you paint up first doesn't become impossible to do with a finite number of decimal points and your argument about splitting a cm has no bearing on that.
In the UK, we also use stone to measure our weight. I'm 9 stone and a bit. Why is it more useful to be able to say I'm, 60kg. That's more precision than I want to tell someone my weight.
Don't people assume you are rounding when you give them whole numbers over there when you give them nice well formed number like 60? If you tell ordinary people you weigh 60kg I'm fairly certain everyone would assume you weight roughly 60kg or you could always say "roughly 60kg", I really don't see the difference. If it's a convention everyone uses you would presumably think telling someone you weigh 60,3kg is more precision than you want to tell someone.
I know this is an unpopular view with geeks, but if someone could please explain what problem metric solves, I'm all ears (And please don't trot out the space shuttle imperial vs metric mix up FUD).
The point of standardization is that it costs society is less when it doesn't have to convert or adapt all the time and I don't mean your country in particular, I mean for the whole of earth. It would also remove a fair bit of confusion not only from trying to understand what a yard, furlong or pint is but worse things like there being more than one mile unit. If you can convert almost the entire earth into using an Imperial system I'll be happy to jump on that instead, it sure would be simpler if everyone used the same system. That FUD as you called it is called confusion and I don't see why you should ignore a perfectly valid point when we are just a few countries short of eliminating those types of mistakes forever.