My father is 84. On average once a week he calls me in a state of confusion and despair that he can’t do something on the computer. 100% of the time it involves logging in to a website or paying for something. This is when I’m so happy he has a Mac - I open Messages, find the last message from him and click on the Share Screen icon. We then complete the activity together, as if I’m sitting next to him. I’m always surprised how few people know this is built into macOS.