I'm not in favour of retaining imperial measurements for sentimental or patriotic reasons.
I think that some of the imperial system units are excellent at times – specifically those times when you want to make it clear that don't give a rat's a**e about precision!
People here in Australia still talk about inch ants, not because some ants are 25.4mm long but in reference to a particular variety of bloody big ant with a venomous sting.
When people here talk about something being miles away, that's just short for "a long distance." A long distance is of course a moving target, for a suburban person 5km is a long distance to walk to the shops but in rural areas it's normal to drive over 50km to the nearest decent-sized town.
Pounds and ounces continued to be used for the public announcement of a newborn baby's weight for years, but that's now dying out and these days the only time you ever talk about pounds is when gossiping about someone who's carrying too many of them around the waist.
I am quite happy buying milk in litres, bread in grams and even beer in half litres.
The conversion to metric in Australia saw some interesting moves worked out to switch over with food.
The pint bottle was still a quite convenient size for milk that was primarily delivered at the time, so this switched to be 600mL. That size was then kept when milk largely switched to square cartons, for both the smallest size available in plain milk and also the standard size for flavoured milk such as Farmer's Union Iced Coffee, legendary for making South Australia the only place in the world where Coca Cola is outsold by a milk drink.
Glass sizes in pubs seemed to be quite convenient, so they basically kept them. These days you generally get beer in glasses which are close enough (i.e. rounded off to 570mL, not 568mL exactly) to a pint in volume. The common smaller size 'middy' (285mL) and 'schooner' (425mL) glasses are roughly equivalent to ½ and ¾ of a pint each. Does the average punter at the pub know this? No, and it doesn't matter either.
You'd almost never buy a 500mL bottle of beer though. Beer is generally a stubby (375mL, same volume as a can), longneck (750mL, same as a normal bottle of wine) or more recently 330mL for 'premium' domestic beer, imported beer or locally-brewed beer.
Other drinks are commonly sold in cans of 250, 375 and 500mL (½, ¾ and 1 full "metric pint" if you take a metric pint to be 500mL) or plastic bottles of 600 and 750mL.
There was one Mars probe which failed shortly after launch because a plus sign had been used instead of a minus sign in the software - or the other way round. That's not a metric / imperial muddle up, but the end result was the same!
You must be thinking of a different one.
The one referred to here was the Mars Surveyor '98 fiasco in which both probes (one orbiter and one lander) crashed into the surface of Mars within a few months of each other.
The Mars Climate Orbiter was the one with the imperial unit issue causing it to approach the planet too close for the orbital insertion to work properly, attributed to one software program calculating the total impulse (i.e. the change in momentum) from a number of thruster firings in pound.seconds instead of the required newton.seconds which was in the specification issued to the contractor Lockheed. Even if SI units was not involved, calculations involving force are a recipe for disaster with the imperial system because of the confusing difference between pounds (mass) and pounds (force) where the SI has kilograms (mass) and newtons (force) to remove the possibility of ambiguity.
The other part of that mission was the Mars Polar Lander, which arrived at Mars a few months later and then crashed into the surface. This one had the sensors falsely detecting touchdown while it was still descending, which caused the engines to stop firing and the lander to fall to the surface.
As I wrote earlier, the root cause of the error was the decline in engineering competence at NASA. This peaked during the Apollo program when they had a good bunch of administrators who knew their role was just to support the engineers and give them what they needed to get the job done, which saw such feats as Apollo, Skylab, the Voyager probes and the beginnings of the Space Shuttle program. During the early 1980s and then again during the 1990s, NASA grew into a bloated bureaucracy that had too much management, directly leading to various high-profile failures of unmanned missions and the losses of the Space Shuttles Challenger and Columbia.
There is actually a reason for that though. 1024 better reflects how computer technology works, and what sizes things therefore tend to come in!
Except it doesn't work that way in hardware these days! The external drive sitting on my shelf here is a 4 TB drive which has in fine print that it is 4 trillion bytes (i.e. 4 x1000x1000x1000x1000) and not a convenient x1024 number.
My internal drive is 500 GB, not 500 GiB or 512 GiB. Even SD cards (despite the sizes available being 2, 4, 8 etc) are sizes in GB (i.e. 32x1000x1000x1000) and not in GiB, makes you wonder why they don't forget putting up even a pretence and simply make them in round number sizes like 50 GB or 100 GB instead of keeping up the charade.
Sure, RAM still comes in x1024 numbers, but that's very much the exception to the rule now.
Keeping things in the x1024 system only benefits certain programmers and hardware designers, but for everything that gets displayed to end users the x1000 system is better. An operation needs to be done to display that info on the screen, multiplying it by a slightly different conversion factor is not going to be a drain on performance.
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Indeed but one has to take preference over the other and people will moan about it - milk is sold as you suggest but this is a volume rather than a weight. Listing weights would be a bad idea - imagine having to divide by 9.81 m/s² or whatever the imperial equivalent is.
+1 for knowing the difference between mass and weight.
Of course, it doesn't help the imperial system's cause that pounds are a unit used in both!
). I am also approximately 100kg 
