Mike had a nagging sense that it was right on the tip of his tongue.

But he could not shake a nagging sense of guilt.

There was that nagging sense of a mystery again, something to do with her.

She also developed a nagging sense of social justice.

Still, we had a nagging sense that we were missing something.

But even after two spoonfuls, I still had the nagging sense that something wasn't right.

But he began to have a nagging sense of guilt.

And he could not shake the nagging sense of familiarity.

Now he knew why he'd had that nagging sense of having seen her before.

Now, she had the nagging sense of having missed something vitally important.