Whenever I get to berating myself for missed opportunities (probably biggest was turning town a job at FB in 2007) I try to also think of the right gambles I've avoided: turned town early positions at 2 failed search engines, turned down job at Yahoo in 2005, etc...
I find those smart choices don't come to mind as easily as the missed big opportunity choices, so I have to work to keep them in mind too.
Whenever I entertain the "employee #N" daydream, I fantasize that I might have negatively altered the trajectory of the company: butterfly effect and all that. By hiring me, they might have missed out on hiring engineer X, who sneezed one day at lunch and gave designer Y a cold, who became inspired to doodle a graphic while out sick, which subconsciously cheered up a key customer prospect because of something his daughter said that day, which leans him towards signing a big contract, and that made all the difference. Or perhaps it was a more direct action or inaction of mine that changed the course of history.
Is the success of an endeavor highly sensitive to small perturbations in the timeline? I'm guessing most of us don't buy into the mythology of the all-powerful Idea and Founders. Every employee and action matters. The details matter. If I could go back in time and swap in for employee #8 at MS, it would probably no longer be the MS we know. Or perhaps we wouldn't know of it at all.
Perhaps best not to sweat these missed opportunities, and instead keep making whatever we're doing right now the next MS, or whatever you define as outrageous success.
The butterfly effect is good for millions of years--maybe, but giving Hitler a cold in 1925 definitely would not have altered his trajectory in the least (blah blah blah goodwins law blah blah blah) there's just so many other things at work that most small things do very little to decide the success or failure of a company -- despite all the stories people love to tell about fedex's last $25,000, if the founder had gambled the money away instead of quadrupling it he woulda just found an investor or bank willing to back him and fedex would be in the same place it is today.
for those who don't know it, it is a basic human trait that failure is more impactful (e.g. you think of a missed opportunity more than the ones you took) than success, it's called negativity bias[0].
Negativity bias is how a negative event is more impactful than a positive one, but turning down a job is not a negative event.
It may later seem like it was a loss, so some form of retrospective loss aversion might be more appropriate to apply to this phenomena: http://en.wikipedia.org/wiki/Loss_aversion
On a general note wrt. failure/success then we actually tend to slightly exaggerate our successes when remembering them, and similarly downplay our failures.
Out of curiosity, why would you characterize avoiding Yahoo! as a right gamble? Were they in a really tumultuous period at the time? While not particularly hip, they're still probably the hugest company to survive the dot-com bubble.
I find those smart choices don't come to mind as easily as the missed big opportunity choices, so I have to work to keep them in mind too.