I think though, that most opportunities are built upon the foundation of previous, smaller ones gone well. So while each is bigger than the earlier; progressively they're only slightly larger.
Maybe, what looks like a really big opportunity out of nowhere is more like a wave on an ocean in which we've been able to put ourselves. It can be hard, but I like trying to make myself look at things this way, because what happens is I see that there are little opportunities all around us - no matter where we are.
Very likely, someone with what looks like a big opportunity had a lot of good execution behind the smaller ones we didn't see.