Most web designers and developers avoid getting feedback on their work because it can be time consuming, frustrating and even scary. But it doesn’t have to be that way. When done right, you can gather feedback that will inspire you, give you a fresh perspective and push your work to the next level.
https://www.hongkiat.com/blog/7-steps-to-better-website-feedback/
You’re doing something wrong if you’re annoying your customers in the process of trying to get their feedback. Are the responses from whatever percent of people actually do respond worth the nuisance this popup is causing to the majority of visitors?
http://overit.com/blog/collect-customer-feedback/