For the Y2K deniers like justwantedalaugh (although to be fair, they're just saying "nothing happened" and totally ignoring the vast amount of work that went into preparing for it so that nothing would happen
- although tell the women who had abortions because someone had missed that particular system when calculating risk of abnormalities
), I'll repeat again what I've said about the Millennium Bug
If lots of people hadn't put in lots of work at the telecoms company I worked for (as did lots of people in all the other telecom companies) in preparation (because telecoms had loads of legacy systems cobbled together), then at the Millennium, not only would your phones (both landlines and mobiles) have stopped working
, but you wouldn't have been able to get money out of ATMs
(because they need telecoms links to operate), use credit cards
(because they need telecoms links to operate), find out your balance even inside bank branches
(because they use telecoms links to operate), listen to the radio
(because the transmission uses telecoms links to operate), use the internet
(because it uses telecom links to operate), trains would have had to stop running
(because the signals use telecoms links to operate) or watch TV
(yes, you've guessed it, because the transmission uses telecoms links to operate).
So yes, just like the Millennium Bug 
BTW: some of these things may become issues again as a result of Brexit. If they aren't sorted again and soon , you may well lose TV links, credit card authorisations and mobile and telecom connections with the EU as the UK Government is being very slow to sort some of the legal issues that allow these to operate, like GDPR and data sharing. Friends still in the industry are pulling their hair out at the complacency of the UK Government, which doesn't seem to have a clue about the far-reaching impact of what it is doing and the hard work that still needs to be done to prepare for it. 