HI again!
I just suddenly felt the urge to comment on some part of your daily life which for a standardized European seems rather peculiar and not very logic at all. Why don't you follow the simple metric system?
First let us take your gallon which you all seem to be so upset about the price of.... What IS a gallon really?... and how was it defined?.....The word seems to come from the latin "galleta" meaning wine jug....... I can't even start to grasp the logic of it... just read this part from the history yourselves....:
In the Roman period the term gallon was used to represent the general idea a capacity or volume of material, and seemed to have been applied to both wet and dry measures. The earliest official attempt to standardize the gallon was during the thirteenth century when Edward I set a standard of eight pounds of wheat; but gallons with eight pounds dry weight (Avoirdupois) and others with eight pounds liquid (Troy weight) coexisted with others that seemed to meet no particular standard at all. In 1707, during the reign of Queen Anne, a new standard was written. The English established a Wine Gallon, which was also called the Queen Anne gallon and was defined to be 221 c.c. and was about the size of the traditional wine gallon in England. This is the size of the US Gallon to this day. A beer gallon also had become more or less standardized by tradition at ten pounds of beer (or ale). This was very close to the dry weight of wheat in the same container and in 1824 the English established a liquid measure, the Imperial Gallon with a capacity to hold 10 pounds (Avoirdupois) of distilled water . Because this was after the US became independent of Great Britain, the two countries have since had different units for a liquid gallon. The US liquid gallon holds about 8.3 pounds of water. The "dry gallon" is seldom used in the US.
Well.. if you now have managed to read your way through this, let us go on to other measures. Let us start with some little thing; the "inch", which is more or less 2.54 cm. Where does the inch come from? In English it seems to originate from the latin word "uncia" meaning "one twelfth part". So then it should be one twelfth of a foot, which is locig, but then; how long is a foot, and more inteerestingly, who's foot was it? I mean, I have a rather small foot, and I know many people with larger feet than me! And I am sure that all Americans don't have the sami size of a foot. And if we are talking about an average sized foot; who measured it? And how?
Now, going on to the yard; I do have a small yard outside my house, but it sure is bigger than three feet! And reading about the origin of the word doesn't give much insight into the logic either; "One source says that the inch was at one time defined in terms of the yard, itself supposedly defined as the distance between Henry I of England's nose and his thumb."
And what about "a square-foot". I have never seen a foot which look like a square...
So I am going on to the "ounce", which is a small unit; I have seen some ounces in nature-documentaries, and they sure are not "an ounce small"!! And twelve ounces should be a pound? First; a pound is a little British coin; second it is also a place for cattle. I get really frustrated with this, almost wish I could pound the wall! 
And so the "acre" I just let the encyclopedia speak for itself:
acre, measure of land area used in the
English units of measurement. The acre was originally the area a yoke of oxen could plow in a day and therefore differed in size from one locality to another. It is now fixed as 10 square chains or 160 square rods, i.e., 4,840 sq yd, 43,560 sq ft, or 1/640 sq mi. It is equal to about .4047 of a hectare or 4,046.9 sq m.
Need I say more?
