On a more serious note: I think he is absolutely right.

On a serious note, we are all different people and have our own opinion about things.

It was a serious note on a day of fun.

On a more serious note though, these prices are getting out of hand.

On a serious note, the main bad thing is the added complexity.

There was a more serious note in the secretary's voice now.

He rose, trying to end the meeting on a positive if serious note.

But on a serious note, I hope he fights again.

I would like to end on a slightly more serious note.

The Commission should take very serious note of our position.