I would have to say if you search out the chances you will find them or they will present themselves. This is one of the ways I find people to promote. Not to use and old phrase but... see a need, fill a need.

If you are in an organization that lacks a dynamic enough environment to find chances, move on. If your boss is upset because you saw and filled a need, move on. If your boss directly takes credit for your effort, move on.

To me it is more about whether the environment is conducive to finding or creating opportunities or not.