How do you separate one off angry cancellation comments from real product bugs?

When someone cancels their subscription, their exit survey feedback is usually written out of pure frustration which makes it really hard to figure out what went wrong. Half the time people complain about a feature just because they couldn't figure out where the button was on day one not because the feature itself is broken. I've wasted weeks redesigning things based on noisy complaints that didn't actually matter.

How do you filter out the emotional feedback from the actual workflow gaps when planning your next quarter?