My favorite one on iPhone is the Apple Health app. Marginally useful to track some trends, so I was using it occasionally. Every 2 weeks it will nag you to "Make sure the Health features on your iPhone and Apple Watch are set up the way you want them" with a banner that takes up 1/3 of the screen. There's not even a "maybe later". No matter what you do, it comes back every 2 weeks. Sure, I can "just" close it. After 5 years, I've closed this stupid nag close to 150 times.