For all of the people working on a startup or having an idea, I just found this interesting link about the launch of Dropbox.
Here the founder pitched his idea on Hackernews and not all responses are positive, while some say it's genius others tell him it doesn't sound like it could go viral or that it isn't scalable. I recognized this in my own products.
It proves a point that although criticism and feedback is good, it is just other peoples opinions and you should always stand by your idea and keep pushing as long as you believe. Good luck today and enjoy the read!