When you're a first time founder, nobody cares about you because they don't have any sort of relationship with you yet. It's really hard to get real true feedback from people. The investors know that you know more people and are incentivized to tell you nice things so that you'll continue being nice to them. When you're a fast time founder, you're less useful to an investor in that way. They can treat you without the kid gloves or the they don't wrap you up in cotton wool as much.