Shared User Accounts
I live with my wife and two boys and as you'd expect we have lots of accounts for lots of different services. What's odd is that the models for the accounts vary quite considerably.
For banking, gas, electricity and water my wife and I have joint accounts - we are jointly responsible and either of us can make changes. Where they offer online services, we each have our own login but are presented with exactly the same data. It's quite a standard user setup from a system point of view.
A lot of online only services still work on a single one account one person basis. We use Amazon Prime. We've both had Amazon accounts for years but when it comes to upgrading to Prime we're not both going to pay the premium. And if we want to read the same Kindle ebook we're not going to buy it twice. So, we end up using the one account and Amazon, who are famous for their user behaviour tracking and algorithms, lose sight of one of their users and what's really happening. That can't be good for them either.
Both Microsoft and Netflix seem to have recognised the need for shared family accounts - it's one subscription per household, not one per person. You set up each user with their own login and they can then save their own favourites, watch lists, game progress, etc. It also allows parental control over children. It's secure too - limited to a single local network so you can't go giving access to anyone outside of that.
I think more services need to recognise how things are really used and adapt their account models to fit. We need special accounts for couples, families, work teams, businesses, charities, etc.