Experience might be the best teacher, but it's also often a pretty embarrassing one. Walking face first into a pole is a great way to learn to watch where you're going, for example, but you'd probably hope to do it on a deserted street not in front of a crowd.

Which is why you have to give the founders who responded to a curious Quora questioner who asked, "What are some critical mistakes you made, and how did you overcome them in early stages of founding your company?" a whole lot of props. 

Putting embarrassment aside, these honest entrepreneurs bravely opened up about their own missteps to help others avoid doing something similar. Let's all do them the honor of trying to learn from their mistakes.

1. I shipped too early.

Orthodoxy in Startupland is that it's better to ship an imperfect product early and learn quickly from your mistakes (think Zuckerberg's famous former motto: "Move fast and break things") than to chase perfectionist while the market laps you. But according to Jason M. Lemkin, co-founder of EchoSign and NanoGram Devices, it's entirely possible to make the opposite mistake. In fact, he's made it twice.

"This is a really tough trade-off. The money is being spent. The demands are high. In both my start-ups, I shipped product too early," he confesses. "With hindsight, in both cases, I think we should have held off another 90 days. That wouldn't have killed either company, but we would have avoided a lot of the issues shipping a too incomplete product."

"My lesson learned: be intense and 100 percent committed. And when you are ready -- Go! But. Some things can't be rushed," he concludes.

2. My co-founder and I didn't have chemistry.

This one is from former Touchstone Semiconductor CEO Brett Fox, who used his answer to relate the story of how he soldiered on with an engineering VP -- whom he calls "John" -- even after John threatened to take over the company and push Fox out.

"John was a brilliant engineer. John was a guru. And yet, John was wrong for my company," explains Fox. "Why? John and I didn't have chemistry...  More to the point, my gut was telling me that John wasn't right for the company. But it's so tough to find a really good VP engineering that I ignored my gut. At least for me every time I ignore my gut instincts I usually pay the price. And I definitely paid the price regarding John."

The takeaway lessons? Not just that you need to trust your instincts, but that you and your co-founders really, really need to align personally as well well as professionally.

1. We accidentally didn't ship to half our customers.

Beauty samples subscription startup Birchbox is having some tough times at the moment, but according to co-founder Katia Beauchamp this is hardly the worst the team has seen.

When the company was about a year old, "something happened with our customer ship file, and thousands of customers received two boxes, while thousands more received nothing," Beauchamp relates on Quora. "To make matters worse: it was the holiday season, and we had no extra box inventory to ship."

How did the team respond to a situation that sounds like just about every CEO's worst nightmare? "Every single person at the company became part of customer service. We were so lucky to have talent leading the team and organizing a group of people who had never had direct interactions with our customers. It was not pretty, and it was insanely hard work (our actual customer service team bore the brunt of it), but it might be one of the best things that ever happened to us," she concludes. "We learned what we were made of."

At least there's a silver lining then, and that grit is probably coming in handy while the business weathers its current crash crunch.

Are you brave enough to share your own biggest mistake in the comments?