The mind basically is going to determine risk to your happiness and use that to make an educated decision.
Some people may be seen to make terrible decisions as they lack forethought. This is because of the amount of variables their mind is able to conjure up.
Let's for instance use a math equation for this.
Mind A - Small intellectual knowledge base
X + Y + Z = 7 value forecast of negatives
Mind B - Large intellectual knowledge base
A + B + C + D + E + F + G + H + I = 47
The larger knowledge base gives you more variables you can work with which increases the ability to forecast an accurate picture. You could also think of it in terms of picture quality. The more higher the picture resolution the more data is included however it makes it much more precise and clear. The lower the picture resolution the less data is included making the image fuzzy and less precise and clear.
However sometimes forethought will include a large amount of assumptions. Assumptions are unproved facts. This increases the possibility that you will not do whatever it is you are trying to decide on. This is not in your favor most of the time. However if you don't have a precise picture you generally will just choose to do whatever your emotion wants you to do which inevitably will throw you into some very diverse and crummy situations.
The trick is to learn how to prevent yourself from over assuming yet still being educated.