|True, to a large extent I have *accidentally on purpose* seen a good shot just sitting there waiting to be seen. Or I've seen it about to happen and took advantage of the moment. Now that I have a modest studio setup I can control the environment, light, subject etc...but even so, still tend to look for that unexpected 'Hey! wtf was that?!' and catch it if I can.
And there are numerous shots I see, virtually every day, just waiting to be captured. Sadly I am usually either on my commute to work or at work when I see them, and it kills me to see what I miss.
And some shots just happen too quickly to be caught even if you did have gear ready to go - the action is so immediate that you are torn between watching it with your own eyes, or trying to capture it with the camera's much more fickle one. In these cases I go for the former.