Things that work for me:

1. Discuss with your manager if it's ok to cancel when you don't have anything to talk about. Sometimes it's all fine.

2. If you're unsure of what to speak about, ask the manager to bring up what he wants you to talk about. My current one always ask me to rate my "happiness" with things are going, I like it as a starting point.

3. Try to reframe how you see your complaints. Part of our jobs is to complain: to notice the problems and to bring them up to the ones with decision power to fix it. I try to always put my complaining in this light, both because I think it helps how others see me, but also because it helps me to identify better what is a genuine problem and what is just a personal annoyance.