Visualizing positive outcomes takes effort
People tend to have a stronger tendency toward seeing the negative side of things.
When you mention an opportunity to them, they see all of the pitfalls and know of some story of doom associated with it.
You should work on seeing the positive side of things instead.
Picture the best possible outcome whenever an opportunity presents itself.
By doing this you will start to see ways of achieving success instead of failure in all of your pursuits.