What services do you use to build your web app?
Have you ever had experiences where you're marketing your product, and people downvote it or start dissing it? And often it's not because of your product per se, but because of personal issues that they have themselves - like often they're just jealous, or they hate the fact that you're charging money for the product.
I find this to be one of the worst things about marketing and putting yourself out there. I know I should just ignore people like that, but it's always hard to not take it personally.