Things were very different 15 years ago. People bought records in shops. Trousers didn't hang around people's knees. What we thought were smartphones were essentially bricks with buttons on them. Operating systems were fifty shades of grey, and not in a sexy way.
And then Apple launched OS X.
It wasn't a surprise - OS X 10.0 had been unveiled at MacWorld Expo in 2000 - but consumers could actually get their hands on it in 2001 for the princely sum of $129. It looked and felt amazing: a quantum leap from the ageing Mac OS, and in a different league from Windows 95.
It felt like the future - and over the next 15 years it evolved to become even better. These are our 10 favorite OS X features of all time.
1. The Aqua user interface
Do you remember the bit in The Wizard of Oz when the world went from black and white to Technicolor? That was Aqua, the interface whose design goals included making people want to lick it. The Aqua interface unveiled first in iMovie and then in OS X 10.0 was stained glass in a world of Windows, and we have fond memories of trying to imitate it on PCs using theme apps such as WindowBlinds. While it's been toned down a bit over the years OS X remains a very lickable operating system.
2. Spotlight searching
Spotlight was the replacement for Apple's Sherlock system search, and it debuted in OS X 10.4 Tiger back in 2005. It indexed your entire system to enable lightning-fast searches, and it became better still in OS X 10.5 when Quick Look instant previews, a calculator and a dictionary were added. Spotlight was significantly enhanced in OS X 10.10 Yosemite, and we use it as an app launcher, Maps searcher and Wikipedia interrogator. It's baked into iOS too.
3. Time Machine
OS X 10.5 Leopard introduced Time Machine, which addressed an age-old problem: how do you persuade people to make regular backups of their data? The answer, it turned out, was to do it for them. Time Machine takes snapshots of your system, enabling you to travel back in time to recover individual documents or items such as Calendar entries and doing so in a very simple and attractive way. We've lost track of the number of times Spotlight saved our bacon.
4. iChat AV
It may seem limited and clunky by today's messaging standards, but iChat and its video-capable successor iChat AV were pretty exciting at the time. iChat debuted in 2002 with support for AOL Instant Messenger - ask your grandparents - and added audio and video chat in 2003. Four-way video chat arrived in 2004 with the ability to connect to other messaging services, but Apple canned it in OS X 10.8 Mountain Lion in favour of iMessage (now Messages) and FaceTime.
5. Boot Camp
When Apple moved to Intel processors in 2006 something unthinkable was suddenly possible: running Windows on a Mac. Rather than leave it to the hacking crowd, Apple decided to make running Windows as simple as possible - so it created Boot Camp as a beta in OS X 10.4 Tiger and included a finished version in OS X 10.5. The move wasn't as odd as you might think, because it gave Windows users yet another reason to switch to the Mac: you could run bespoke business apps and demanding games natively instead of inside an emulator.
6. PDFs everywhere
Where previous Mac OSes used the PICT file format for graphics and text documents, OS X chose PDF instead. With system-level support for the format - the Quartz graphics system inside OS X, which is responsible for OS X's peerless text rendering among other goodies, is based on PDF - viewing PDFs and printing to PDF were and are utterly effortless, and so useful that we'll forgive Preview's tendency to crash for no good reason and its habit of locking up entire Macs with it.
The company responsible for OS X 10.0 was Apple Computer; by OS X 10.10 it was just Apple, because Apple was no longer just about computers. With more and more Mac users owning iPhones and iPads too, Apple decided to make them work together with OS X - and it did that with a feature called Handoff, introduced in Yosemite. Handoff enables your Mac to take phone calls and messages from your phone, open documents you've been working on in iOS, and switch on and connect to the iPhone's Personal Hotspot.
AirDrop is one of the best demonstrations of Apple's "it just works" approach: from OS X 10.7 and iOS 7 onwards, you could AirDrop photos or files from one device to another with a single tap. AirDropping between iOS and OS X wasn't possible until OS X 10.10 Yosemite, and it's only available on devices with both Wi-Fi and Bluetooth LE, although Mac to Mac AirDropping is supported on Macs going back to 2008.
9. Quick Look
How many hours have we saved thanks to Quick Look? Instant file previews at the tap of a space bar might not sound like a big deal, but when those previews are of anything - of documents and images, of movies and music - it's a massive time saver, especially when you're trying to find an audio clip, video or image. Quick Look first appeared in OS X 10.5 Leopard, although it didn't get support for animated GIFs until OS X 10.7.
We've left the most valuable OS features until last. The accessibility features in OS X make computing easier for people with disabilities. Dictation, Voiceover and Braille displays help people with blindness or low vision; FaceTime, iMessage and captions are a boon for people with hearing difficulties; and Switch Control, Slow Keys, Sticky Keys and Dictation can help people with poor mobility. The tech industry is fond of hyperbolic claims, but OS X's accessibility features have been genuinely life-changing.