We’ve all heard stories about the friend or uncle or co-worker who could have invested in, say, Apple long before the company hit big–the sad tales of missed opportunity and phantom millions. What’s it like, though, for the angel investors and venture capitalists who have the same would-have-could-have-should-have regrets about some of the most recognizable start-ups in the tech universe? Business Insider decided to ask eleven otherwise successful investors all about it.

Anecdotes abound from Venrock’s David Pakman (missed Twitter’s round C financing because he “was still getting [his] sea legs in venture”), Ben Lerer of Lerer Ventures, who passed on or didn’t pursue Foursquare and Uber because he didn’t trust his gut, and Union Square Ventures’ Fred Wilson, who missed out on Airbnb because his team “focused too much on what they were doing at the time and not enough on what they could do, would do, and did do.”

While a couple investors were too green, or too broke at the time, there are common threads running through most of the stories. Namely, trust in exceptional people  even if you can’t quite grasp their ideas; listen to your intuition rather than focusing on why something won’t work; and anyone who can do something better, even in a crowded market, is worthy of a second look. These are broadly applicable lessons, whether you’re evaluating a sales pitch or considering a clearly talented candidate with a résumé that reads a bit thin.

As a bonus, check out both Fred Wilson’s in-depth first-person look at passing on Airbnb over at A VC ^[1], as well as a series of email exchanges between Wilson and Y-Combinator’s Paul Graham (republished by Graham ^[2] with permission), who was urging him to consider the fledgling company.

Read more at Business Insider ^[3].