The imperial system originated from 'real life' sizes, and therefore is far less arbitrary than the metric system in many ways.
An inch was based on the length of one's thumb from the tip to the first joint. A yard was from the tip of an extended arm to the nose. Weights and volumes were based on common real life things in convenient or regular amounts. The subdivisions were made to accomodate other smaller common things - it turns out that 36 thumb lengths is about the same as the tip of an extended arm to the nose, and 12 thumb lengths the same length as an 'average' persons foot. So 3 feet to a yard, and 12 inches to a foot.
In many real world situations, that's very convenient. A third of a foot is 4 inches, and not a decimal. A quarter is 3 inches and not a decimal. A 6th is two inches and not a decimal.
Often it doesn't obey a single base, but that's the sort of thing only modern geeks worry about in the real world.
A thou (thousandth on an inch) is a very good unit for accurate measurement until you are in very high-tech situations. From piston - cylinder clearences to surface finish, thousands of an inch proved to be very useful without being excessively small or excessively big.
Any engineer or tradesman worth his salt can work in both metric and imperial - to ignore one is limiting oneself.
It's funny, but people seem to dislike the imperial system just because they aren't used to it, or weren't taught it, without actually knowing if it's any use. It is. Indeed, most equations of physics work with both, just with different constants - i.e. 32.17 feet per second per second for gravity, rather than 9.81.
I'm happy to use both. I personally find that for estimating purposes, inches, feet and yards are much easier to visualise, whilst millimetres are better for accurate measurement when making something (that was perhaps original estimated using imperial - like a pace being a yard, rather than a metre [which is an uncomfortably large pace]). For accurate machining work on classic and modern cars, I work in thou.