At 10 years old, I lost a trillion dollar bet to my older brother. I bet him it was Wednesday. It was actually Thursday. I was very sure of myself (for reasons I can't recall), and saw a good opportunity to shave off some of the debt I owed him. Luckily, he has yet to call the debt. At the time, all I felt was keen embarrassment at my stupidity. As time went on It became clear I had learned a valuable lesson about taking deals that seem too good to be true.
Though mistakes that I make can be painful in the near term (and sometimes in the long term), I've found that they're a critical part of how I learn. I'm fairly certain that the mistakes I made which led to the end of Tutorspree taught me far more about how startups work than immediate success would have.
Success feels good
Success is usually idiosyncratic. Strategies that lead to success are self-validating. We build narratives around the cause and effect of success based on incomplete information and our own biases . This makes it very easy to falsely attribute success to the factors that are easily seen without doing the work necessary to properly understand what happened. This tendency gets even stronger when we're looking at our own successes. At that point, ego starts to discount things like luck, which are frequently a huge part of success. Because success makes us feel good, it lulls our faculties for critical thinking, which almost by definition means it is harder to learn deep lessons .
Making mistakes doesn't give us the same kind of happy feelings that success does. Because the mistakes hurt, we investigate them more closely. Because we're thinking critically and comparing causal chains leading up to and flowing from mistakes, we're more likely to consider complexity and examine why things really happened as they did. That doesn't necessarily mean that each time I make a mistake I learn a critically important lesson about myself, but by thinking hard enough, I generally do learn something useful .
Mistakes vs. Failure
Near as I can tell, I'm not alone in believing that mistakes are a valuable tool for learning. In fact, in Silicon Valley, there's a tendency to talk about failure as a point of pride. But there's a disconnect between how we talk about Failure (intentional big "F") and how we talk about mistakes. While the internet is littered with post-mortems on failed companies, it's rare to find founders or investors who will freely admit to being wrong about a public comment or investment .
That doesn't make sense given what we know about mistakes. It does, however, start to make more sense with the addition of two other factors. The first is the increasing permanence and public nature of all media. It's relatively easy for me to admit mistakes to small and trusted groups because I don't fear malicious repercussions. As that circle expands, the difficulty of admitting the mistake increases because I don't trust the intentions or actions of everyone in it. In the competition between wanting to learn by admitting mistakes and wanting to not be perceived as stupid or attacked for the same, not looking stupid wins.
This directly informs the second factor: increasing obsession with "personal brand." Personal brand isn't a new concept, but it has become increasingly important to more people because of the pressure to constantly tell the story of your life in public through social media. That publicity + the expanded circle again leads back to wanting to present a perfect image. Through that lens, each instant broadcast that is inconsistent with that narrative and "off-brand" appears to be a public failure in front of an untrusted circle. Not only do we look stupid for making a mistake; the mistake jeopardizes the narrative we've built about ourselves. 
Even if "building a brand" isn't something we consciously think about, knowing how public everything is makes being honest about mistakes hard. So how do we get as comfortable looking at recent mistakes as we are looking at the ones in the distant past? We probably can't - there's too much baggage. But I think there are ways to start moving in the right direction. Recognizing the cycle that makes it hard to admit mistakes is a good start. Developing a close friend, set of friends, or mentor, with whom you can speak honestly is another step. Most importantly, I think we probably need to take it easy and remember that no mistake, public or private, is likely to be the defining moment of our lives . At the same time, cutting some slack for others who make mistakes will likely do a lot to ease the culture of recrimination/fear that has built up around making mistakes. Really, we just need to be decent and thoughtful. Hard, but important.
 Fitting facts into a story is a common trap that seems to go the base of how our brains are built.
 If you happen to be watching the success of someone you dislike, the reverse might be true. Your critical thinking faculties might be working just fine, though your conclusions and avenues of investigation might get clouded by envy or jealousy.
 That might be "be careful when stopping with your new clipless pedals." Maybe small, but better to learn the lesson than assume it was easy.
 Interestingly, you'll see more evidence of VCs admitting to investments they missed than investments they should not have made. See Bessemer's Anti-Portfolio.
 That certainly wasn't always easy. I've had to work on being able to admit my mistakes. The benefits I've reaped by doing so have made it easier and easier.
 Truth is, I haven't prioritized my personal brand that much. I firmly believe that trying to build a brand is the best way to get the reputation of just being a scenester. I think I should be judged on the things I actually do with and for the people around me. That, however, is a completely different topic.
 With the possible exception of Bill Buckner in and around Boston.
 That may mean you lose the chance to show Twitter how clever and snarky you can be. That's a good trade in the long run.