Finding friends who are willing to tell you things that you don't want to hear is hard. Even when you explicitly solicit feedback, most people are hesitant to be critical. So, be patient with friends who are willing to risk having you get mad at them to help you improve. While the truth can hurt, it's best to hear it from someone who cares about you before it's too late.
With romantic relationships and business ideas, it's easy to invest significant amounts of time only to learn that they won't work. Typically, your friends know before you do because they know your blind spots. So, it's strange when you find out that they didn't say anything.
Truth tellers can be rough around the edges, but it's important to look past that and be grateful that they're willing to speak up.