But there's a certain kind of nitpicky person you can never make happy.
When your company is young and immature, there's still a decent concentration of actionable feedback in the nitpicks. Eventually it gets harder to mine gems out of it.
Aye, you've nailed the point. Early on, a particularly nitpicky and oversharing customer can help identify problem areas or get feedback on the product in greater volume than the quiet, happy users. "Early on" being the keywords here.
Nit picky can be fine. Even if they are on a free tier. I have some customers that pay me nothing, and are quick to highlight anything and everything. It's frustrating sometimes, but the product is better for it.
A much more serious issue for us is customers who abuse our staff. And these are sometimes high-paying customers. Shouting and swearing on the phone and on site. And worse.
We've learned the hard way to recognise companies with this culture, and actively (but politely) remove ourselves. Even if it costs a significant, potential 7 figure deal.
The bottom line is that our staff are our greatest asset, not the code, and not the customer - and even one staff member leaving over a bad client is a net loss, regardless of the deal.
We haven't fired many, but we've never regretted it.
I should also point out that we differentiate individual bad behavior from company culture. Sometimes we get a different point of contact, but at some companies it's a culture where everyone does the same thing.
If I was starting a company, I'd prefer to have at least a few nitpicky customers. You might not solve all of their problems, but their over-communication might highlight insightful decisions you could make, that would otherwise be opaque from customers who don't ever talk to you. Emotional, verbose feedback is better than no feedback.
But there's a certain kind of nitpicky person you can never make happy.
When your company is young and immature, there's still a decent concentration of actionable feedback in the nitpicks. Eventually it gets harder to mine gems out of it.