The most useless calendar widget is made by Apple. I constantly forget that someone’s birthday or something important is coming up later in the week.
Now I understand that you can set up alerts and you can set up reminders for stuff. I also understand that you can choose a different size widget. But depending on the size and the amount of events it’s possible it won’t even show you what’s going on the next day in the larger widget as well.
This is forced me to use third-party widgets to display calendar events for the week on my home screen. I hate it because I have no idea if it’s stealing my data.
Bonus Edit! The large widget fails to show you what’s happening today!
The problem is a lack of emphasis. Apple routinely completely ignores basic features and UXD in their apps, for years. If you don’t want to use an app in the exact rigid structure they want you to, you’re gonna have a bad time.
That’s why I only use a handful of Apple apps — the apps that have no possibility of vendor lock-in, and can be instantly replaced on any other OS (e.g. calculator — which also fuckin sucks for anything beyond basic arithmetic).