I've had a lot of great one on ones and a lot of bad ones. They changed towards being great when I started gathering a list of things I wanted to cover or talk about.

One on ones where we make small talk about the weekend are useless to me. One on ones where we can talk through a technical topic I don't understand and I know I have at least a half hour of time to do so with someone who knows the topic well? Very helpful.

Most of the time its only tangentially related to anything I've been working on.