People usually use extremes to narrate an example. Take, for instance, the active man and the passive man. The former is claimed to challenge and defy fate, not content with waiting for opportunities but takes steps to ensure it happens. The latter, on the other hand, takes only what is given to him. He has no initiative and usually defers to the majority. If there are no opportunities, he does not act.
While the active and passive man works, I'd like to include my own model into the picture: that of the opportunist. Now when people usually mention opportunists, they usually say it with derision; the common idea we have of the opportunist is someone who takes advantage of the weak, someone who steals when no one is looking. While that does happen, there are also, I believe, opportunists who do have morals and do not necessarily act that way.
The opportunist for me is the bridge between the active and passive man. At first glance, he seems like the passive man; he doesn't look for opportunities but merely waits for them. However, once opportunity strikes, the opportunist does everything to attain that goal. He transforms himself from being passive to active; he exerts effort and competes with others, even if the road is difficult, in order to succeed. And should he fail, he does not give up and renews his conviction in attaining that which he has tasted but lost.
I'd like to compare the opportunist to a horse. At first, he seems without motivation, just grazing in the field. However, dangle a carrot in front of him, and he'll follow you wherever you go; even if you put several obstacles, the horse will continue to gallop and strain itself until it manages to acquire the carrot. Whereas the passive man would give up at the obstacle, the opportunist follows through. And while the active man would certainly look for the carrot from the start instead of grazing in the field, the opportunist is not without his own virtues.
A prime example is the mediocre student who manages to get an A out of sheer luck. Having tasted what it is to succeed, he exerts more effort in the future in order to retain such successes. His first conscious attempts might only garner him a B or B+, but that doesn't impede him from trying. Soon, after several losses and much effort, he finally attains the A that he once caught, and continues to retain it (he becomes an honor student).
I do think a number of people are opportunists such as that, not exactly possessing initiative at the outset, but given enough motivation and opportunity, will strive to attain something that's dangled in front of them.
It's much worse, after all, to have acquired something only to have lost it, rather than never to have gotten it in the first place (and lost love is painful exactly just because of that).