I've just changed my car, and it's spookily similar to one I had a few years ago: it's the same make, same model, same body style and even the same colour, so I don't struggle to remember which one it is in a car park or which bit does what. It's not completely identical, however. It's newer, and slightly restyled, and the spec's better.
From decent fuel economy and reasonably low road tax to a better stereo and more comfortable seats, it delivers the things my earlier car didn't.
Essentially, the older car was Lion and the newer one OS X Mountain Lion.
As you'll see from our review, Mountain Lion boasts plenty of improvements - but there's nothing show-stopping like, say, Windows 8's Metro UI. It's a bug fix and a polish rather than a brand new OS, a host of incremental improvements rather than a whole new OS.
That means it's no big deal - and that's a big deal.
The Lion King
I don't like upgrading operating systems. When the UI changes - whether it's Apple's inverted "natural" scrolling or Windows' Metro - it takes a while to get used to (or reject) the new way of doing things, and there are always bugs and incompatibilities. Whether it's Windows or OS X, upgrading has variously killed video playback, messed with my Wi-Fi adapters, introduced really, really annoying bugs or rendered bits of hardware completely obsolete.
While Mountain Lion will no doubt introduce its own bugs and annoy me with things such as the iCloud file system, any irritation and inconvenience is on a much smaller scale: it's a polish and incremental upgrade to what I've already got, not millions of lines of brand new code whose wrinkles won't be worked out for another nine point upgrades, so unless Apple's seriously cocked something up the upgrade should be relatively painless.
The price is right, too, a couple of pints rather than a pricey restaurant meal - and if there's anything in this year's model that I don't particularly like or that I really want to see, it's only a few months until the next version comes along.
It's a very iOS-y way of doing things, and that suits me fine: I'd much rather have a cheap and relatively undramatic annual upgrade than a big blockbuster release every three or four years. I want my computer to work like my car does: quietly, efficiently, and without bursting into flames when I just want to go to work.