What makes someone an exceptional Accountability Partner?

What exactly makes someone a good or even great partner?
Many people assume an accountability partner is just someone who says, “How did your workout go?” or “Great job, keep going.”
But I feel like the best partners do something much more valuable.

They ask good questions.
They notice patterns you don’t see yourself.
They help you think through setbacks without making you feel like you’ve failed.
They know when to encourage you, when to challenge you, and when to simply listen.
They don’t need to be experts in your goal—they’re experts in helping another human stay engaged with it.

So I’m curious…
Have you ever had someone who genuinely helped you stay on track with a goal?
What did they actually do that made the difference?

Or, if you’ve been that person for someone else, what have you found works best?
I’m hoping these discussions eventually help us build a shared understanding of what “good” looks like, because I don’t think we’ve really defined the role yet.